Not going to second guess Jon Ralston on Nevada- his track record is too good- plus polls tend to underestimate Dems in Nevada, so it wouldn't be unusual for the Dem to pull it off despite being underwater in the polling average.
Pennsylvania- I just don't see the Senate and Governor gap being as massive as the polls suggest, and Oz overcoming his terrible favorability. For all the focus on Fetterman's health, PA voters haven't much cared about it, but they have cared about Oz's authenticity. Shapiro is killing Mastriano in the polls and that makes sense- Mastriano turns off a lot of voters.
Georgia- feel uncertain about this one, but Warnock barely won last time and the environment has gotten worse for Dems since then. Here again I just don't see the Senate and Governor gap being as massive as it would take for Warnock to win here. Maybe the polls are underestimating Abrams, though Kemp's favorability is not bad and this is still not a state that is particularly blue. But a Senate runoff is a real possibility. At that point all bets are off, especially with Trump announcing his 2024 run soon.
Arizona: lot of baggage there.
New Hampshire: same as Arizona.
Ohio: Vance is a terrible candidate, but Ohio is pretty red and seemingly getting redder. Ryan has run a great campaign, but just not the cycle for him.
North Carolina: Beasley has run a good campaign as well, but again North Carolina still hasn't turned purple yet. Just not the cycle for her.
Wisconsin: Johnson is a terrible candidate, but again Wisconsin like Ohio is seemingly getting redder. Polls have had the toughest time polling Wisconsin and Ohio in recent cycles, so it may not be as close as it looks.
As I said my dark horse is North Carolina. I don't think it is likely, but I'll be happy to be surprised.
All these Senate races are super close and there is a lot of uncertainty about the polls this cycle. So anything from D+2 to R+4 is certainly possible.