The bill in question is
House Bill 436, which would have nullified federal enforcement of gun-control laws. I've heard that there might be enough votes to override his veto, but let's think this through.
First, consider the
governor's response [pdf].
Second, let's remember that people will still be arrested, tried, and sentenced on a
federal level. Is the state going to rally troops to prevent this? Unlikely. These nullification efforts might play well for the peanut gallery, but the avenues for real and lasting change are the federal courts and legislatures.