I'm just getting started with Gourami but am getting familiar with their behaviors.
It sounds like you have two blue males in your tank. Some of the males can be very dominate and aggressive even to other fish. I have a deal with my lfs
that if something doesn't get along in my tank I return for an exchange (or hopefully less aggressive fish).
With that said, I think you will have better luck if you learn to sex your Gourami. The females generally will have a rounded dorsal fin vs the males will have a more pointed dorsal fin. Also, the females belly's will be more rounded. Sometimes it's hard to tell if they are young fish and not developed.
You may try replacing/exchanging one of the blue males for a female and see if that doesn't stop the chasing and nipping.
I don't know if there's a limit on how many females can be together but I'm guessing having just one male might be the ticket.
Hope this helps.