JAMullins beat me to the punch, but I was about to say that Sotomayor's decision in Maloney may be good news for gun owners. She was correct that right now, the settled law according to SCOTUS is that the Second is not incorporated. She appears to be a strong believer in stare decisis (the philosophy that I was wrong before and am not about to correct myself). So, assuming she is confirmed and gets to a case, she would then vote to uphold Heller as settled law.
And, since the Maloney case is upcoming, she would almost certainly recuse herself from it if she gets confirmed in time. This makes it an 8 man decision which would probably be 5-3 in favor of overturning.
The best news is that her court ruled against incorporation while the 9th circuit voted in favor. As a general rule, the best way to get SCOTUS to address a question is when there is a conflict between the circuits. If they had not caused the conflict this early, we would have to wait until all appeals circuits ruled in favor to have true incorporation.
The second half of the question is whether or not she will be confirmed. I read (my personal opinion) her nomination as a test case. Do the Democrats have the power to push her through and are the Republicans willing to fight the battle? I don't see her as a real battle the Democrats are willing to fight hard for, just enough to test the resolve of the Republicans. If she gets confirmed, it is a double win for the Democrats in they get a judge they like and they show their power over the Republicans. This is a green light to do what they want.
If the Republicans do wage war, the Democrats will right her off. They probably already have a second choice ready and it will be much harder to fight the second nomination. If they nominate someone else who is just nominally better (as in more qualified), the Republicans would lose more public support fighting the second chance (be called obstructionist and so on). So, is she the throwaway to prep for someone even more liberal or is she the real nomination? Given her record of being overturned, her record of being temperamental to work with, her "racist" comments, and the comment that shows she doesn't have the sense of a rock (her 'I know this is being taped and I shouldn't say this but, you know, it is where we make policy decisions' comment), I really do not see her as being the best choice for the bench. On the plus side (for her), she does have a reputation for being someone who very carefully crafts her legal decisions using sound legal logic and thinking.