Post a picture of the broken nipple? Those are molded so to fix you would have to use JB Weld or replace the entire tank. I found one on Facebook Market place and paid $100 with the skid plate.

 

I broke a vent nipple and ended up with a small vacuum tube and JB Weld to keep it together and functioning. Gas tanks (and even stock skids for that matter) don't go cheap. If you can't fix it and can't get ahold of that $100 deal Canvas saw, car-part.com should have some in salvage yards near you. Calling the individual yards can be time consuming but it's worth it. I bought a hood for $185 in my factory color (offered for 18 months).

 

 

Yep, that looks like the small one that I broke. You drill it out, epoxy a standard sized plastic vacuum fitting in there, then secure some vacuum line between your new plastic and what's left on the other side.

There are videos on YouTube and often that kind of break will come with an evap code. Easy fix, just let the epoxy dry well and secure the new line so it doesn't break off again. My theory is that the original didn't have enough flexibility which causes our issues.