If its slipping or jumping as you apply pressure, then its a chain/sprocket issue, but if its just derailing the chain, its an adjustment issue.
Those teeth don't look all that bad to me, or at least not bad enough to be jumping the chain. For the chain to get down on the BB like that its likely a derailleur adjustment issue.

Worn teeth generally start getting 'hooked' and the gaps start to oval out in one direction. They start to look like shark fins.
The chewed up tips on the teeth are from rough shifting or partial shifts where the chain didn't just jump to the next sprocket cleanly.