Boy they must be in heaven in that large set up!

I'd just keep an eye on them, they may not nip. Some tetras are worse than others. I can't really tell what kind you have.
I have neon tetras in with my betta & no problems what so ever.

If you can put in more decoartions that have hidy holes & the such it may help the fish live together better, giving them each a safe spot of their own to hide in if need be.

Tetras are school fish though and do best in groups of at least 5 or more.