The mod below is a planet collection mod that introduces and adds several planet mods. I have this mod installed and am playing.
https://mods.factorio.com/mod/kry-planet-mods-lite (by Kryzeth)

However, the "Nitrogen" in the "Fertilizer" recipe overlaps with the "nitrogen" in the three planet mods below.
So, I can't craft "Nitrogen," an ingredient in the "Fertilizer" recipe, early in the game when "Fertilizer" is unlocked.
This happens if any of the following three mods are active.
I figured it out by disabling them one by one.
Is it possible to add compatibility?
If not, I can't disable the planet mod, and instead, I plan to play using only recipes that don't require fertilizer.
Thank you again for making such a fun mod.

https://mods.factorio.com/mod/Paracelsin
https://mods.factorio.com/mod/skewer_planet_vesta
https://mods.factorio.com/mod/shchierbin

The recipe for converting "liquid-air" to "nitrogen" itself is not visible.
It doesn't appear on Factorypedia, either.
On Factorypedia, only the "nitrogen" recipes for the planet mods reported above are visible.

I'm currently not offering support for Space Age. Ask the other modders if they want to provide support for Bio Industries.

@Labsj
I had a similar issue with the Paracelsin mod (https://mods.factorio.com/mod/Paracelsin) and overlapping Nitrogen recipes moving Nitrogen much later in progression.
I found a fix, not my mod but it did help with the nitrogen issue, allowing it to be unlocked with oil processing: https://mods.factorio.com/mod/simple-atmosphere-separation

@Cackling.fiend Love your work :)

Good find @Loaz I was also looking for a solution but I went into the file of the mod. @Labsj It is pretty easy to remove the overrides from Bio Industries if you want to keep the old recipes. In the mod file go to data-updates.lua and find line 432 and change it to this
do
data:extend({
{
type = "fluid",
name = "nitrogen",
icon = ICONPATH .. "nitrogen.png",
icon_size = 64,
icons = {
{
icon = ICONPATH .. "nitrogen.png",
icon_size = 64,
icon_mipmaps = 1,
}
},
default_temperature = 25,
gas_temperature = -210,
max_temperature = 100,
heat_capacity = "1kJ",
base_color = { r = 0.0, g = 0.0, b = 1.0 },
flow_color = { r = 0.0, g = 0.0, b = 1.0 },
pressure_to_speed_ratio = 0.4,
flow_to_energy_ratio = 0.59,
subgroup = "bio-bio-farm-intermediate-product",
order = "ab"
},
})
BioInd.writeDebug("Made recipe for \"nitrogen\".")

if not data.raw.fluid["liquid-air"] then
    data:extend({
        {
            type = "fluid",
            name = "liquid-air",
            icon = ICONPATH .. "liquid-air.png",
            icon_size = 64,
            icons = {
                {
                    icon = ICONPATH .. "liquid-air.png",
                    icon_size = 64,
                    icon_mipmaps = 1,
                }
            },
            default_temperature = 25,
            gas_temperature = -100,
            max_temperature = 100,
            heat_capacity = "1kJ",
            base_color = { r = 0, g = 0, b = 0 },
            flow_color = { r = 0.5, g = 1.0, b = 1.0 },
            pressure_to_speed_ratio = 0.4,
            flow_to_energy_ratio = 0.59,
            subgroup = "bio-bio-farm-intermediate-product",
            order = "aa"
        },
    })
    BioInd.writeDebug("Made recipe for \"liquid-air\".")
end

-- Recipes for "bi-liquid-air" and "bi-nitrogen" aren't needed!

-- else
-- local oxygen = data.raw.fluid["kr-oxygen"] and "kr-oxygen" or "oxygen"
local nitrogen = data.raw.fluid["kr-nitrogen"] and "kr-nitrogen" or "nitrogen"

-- -- Remove recipe unlocks
-- thxbob.lib.tech.remove_recipe_unlock("bi-tech-fertilizer", "bi-liquid-air")
-- thxbob.lib.tech.remove_recipe_unlock("bi-tech-fertilizer", "bi-nitrogen")
-- BioInd.writeDebug("Removed recipe unlocks for \"bi-liquid-air\" and \"bi-nitrogen\"")

-- Replace liquid air with oxygen (from Krastorio/K2) in recipes for Algae Biomass 2 and 3
-- if data.raw.fluid[oxygen] then
--     thxbob.lib.recipe.replace_ingredient("bi-biomass-2", "liquid-air", oxygen)
--     thxbob.lib.recipe.replace_ingredient("bi-biomass-3", "liquid-air", oxygen)
--     BioInd.writeDebug("Replaced \"liquid-air\" with \"oxygen\" in recipes \"bi-biomass-2\" and \"bi-biomass-3\"")
--     -- Perhaps there is no oxygen? But there's nitrogen for sure, so we fall back to that!
-- elseif data.raw.fluid[nitrogen] then
--     thxbob.lib.recipe.replace_ingredient("bi-biomass-2", "liquid-air", nitrogen)
--     thxbob.lib.recipe.replace_ingredient("bi-biomass-3", "liquid-air", nitrogen)
--     BioInd.writeDebug("Replaced \"liquid-air\" with \"nitrogen\" in recipes \"bi-biomass-2\" and \"bi-biomass-3\"")
-- end

-- -- Remove recipes for these fluids
-- data.raw.recipe["bi-liquid-air"] = nil
-- data.raw.recipe["bi-nitrogen"] = nil
-- BioInd.writeDebug("Removed recipes for \"nitrogen\" and \"liquid air\".")

end

save your file and rezip make sure the folder you are zipping has the main files and not another folder called bio industries 2. The name of the zipped file must be Bio_Industries_2_(version number) so right know it would be Bio_Industries_2_2.0.30

You don't have to zip it. The game will prioritize folders over zips. I you remove the version from the folder name it still works.

Btw. I do accept pull requests if the solution is somewhat polished. A good solution would be to put the nitrogen name in a variable and use the existing one from other mods if it's present.