The Field Office building needs to be built within 100 tiles* of a biter nest, but this can be hard to estimate. Especially if you let spaghetti get out of hand like me as it can push the buildings further and further out. A nice QoL in my opinion would be having a visible range when trying to place a Field Office to indicate what is within range of a nest. Immersive Colony Building has a similar circle to what I'm thinking with it's Depo building. Except it centers around the Depo and shows up when a built Depo is selected while in this mod I figure it would be most helpful centering around the nearest nest and appear when holding a Field Office in hand.

Also great mod so far. I'm really enjoying it. It's the only mod I know of that applies external pressure without using the vanilla "enemy waves" style. Which makes it really unique.

Go ahead and stress test the distance, you'll be surprised.
As of the last update I was running biters at 7 chunks, so ~224ish tiles. It gets to the point where you couldn't see the limit without placing from the map. I would alternatively suggest it is a "out of range" popup on the placed field office itself, for instant feedback on placement.

Side note for notifications, the "no power" popup on the field office only stays for a moment before disappearing, making an unpowered field office look like its just out of biter range instead for a new player.

And yes, an updated tooltip :v

Oh yeah, simply having the "out of range" warning take priority over "out of materials" and "out of power" warnings might work and sounds a lot simpler. Means the player immediately knows if it's in range or not instead of finding out later. The experience that really annoyed me was I finally placed my ghosts to automate science and than found out that the last office was just out of range. I should just build closer to the nests in the future though. Was just lazy and didn't wanna belt everything over there before I had automated belts.

Will work on a popover, and the electricity overlay issue is a pain in the a** but I can't figure out how to solve this yet :/

Yes, out of range is an excellent way, instead of adding informations constantly