Not a lot. It's always a wildcard with a new administration and he's getting mixed support from both parties ahead of confirmation hearings so he might not even get the job.
He's an advocate for science and spaceflight, which is good. But he's also said concerning things in the past about NASA selling off assets and missions to private bidders. He's also very keen on the Dragon mission to repair Hubble, which is a double edged sword. Going off half cocked with a system that's not ready yet could have disastrous results, but properly developing a capability we never fully realized with the shuttle would have immense and long lasting rewards. I'm not confident which way he's likely to go on that.
He's also coming in with an administration where accountability and rules are liable to be hypotheticals. He also didn't write most of the rules like Nelson did. That means for good or bad he's at least likely to achieve any of his ends that fit in the budget. But at the same time, he's tied to Elon Musk. Trump and Musk have had falling outs before. Another one could put Isaacman on the outs with him.