It wasn't that long ago that Aaron Nola was considered to be one of the absolute best pitchers in all of baseball. The guy eats innings, strikes out batters at a high clip, throws a ton of strikes, and is nails in the postseason. On paper, he should be a guy that every team would want on their roster.
However, there are a few problems with targeting him for the Red Sox's rotation. First, he is showing signs of decline. In two of his past three seasons, he has posted mid-4 ERAs and has shown some intermittent issues with the long ball. At 30 years old and looking for his final big payday, there is going to be a lot of crossing of fingers in hoping he will bounce back and age well.
The other problem is the Phillies. Nola would greatly prefer to stay in Philadelphia and the Phillies would love to have him back with both sides agreeing to have discussions after the 2023 season. Getting in a bidding war with Dave Dombrowski is not a wise decision in most circumstances and given that most observers think that Nola is going to require at least six years at a decently high AAV for his next contract, that is a lot of money to tie up in a guy that has some warts to his game.
If Nola hits free agency, the Phillies and other teams are going to be in hard on him and he is just not worth pushing all in on with better options like Sonny Gray and Jordan Montgomery on the market.