i have a jbj 24g nano with the stock PC lights and i have a pair of latz and 2 gbta's in there for a few months and they are fine. my nem actually split when it was 6" and now i got 2 6" nems in the tank. i tend to run my lights longer in this tank and also cooler around 74F.
I've seen it done before, but it's not recommended. The nems tend to be on the edge of their healthy lighting requirements with that little light. I wouldn't do it unless I had a stronger retrofit in there. The clowns will be just fine, but be sure to buy small, young ones.
If you supplement in more lighting you would be fine. I replaced my filter for a BC skimmer, added a EcoXotic panorama 50/50 strip, and subbed the white for another actinic...1 gbta is LOVING it, got a pair of onyx, sebae, and a true...