Orlando - they are committed to Wendall Carter as their starting C, and he's arguably already better than Nurkic. So they wouldn't be making a big offer to Nurk. At guard, they have Cole Anthony, Jalen Suggs, Terrence Ross, Markelle Fultz, and RJ Hampton all under contract next season. They also have Gary Harris as a free agent they may be interested in re-signing. I don't see them as much of a threat to offer Simons a 20+ million/year deal
Detroit - they don't have any cap-space unless they renounce the rights Bagley, and they won't be doing that. Even if they re-sign him quickly for 15M, the most space they'll have is in the 10-20M range, and 20M in unlikely. They have Stewart and Olynyk at C and both are more mobile than Nurkic. And they have Cade Cunnigham, Killian Hayes, Cory Joseph, and Hamidou Diallo at guard
Indiana - looks like the most cap-space they'll have would be in the 15-20M range. At guard, they already have Brogdon, Buddy Hield, Tyrese Haliburton, TJ McConnell, & Chris Duarte. There's no way they'll be using their limited cap-space on Simons. And they already traded away a better C than Nurkic in Sabonis to clear the way for Turner to be their starter. And they may have already lined up a substantial offer to Jalen Smith. They are unlikley to make a 15M/year offer to Nurkic to be their backup C
San Antonio - with their 3 first round picks and the cap-hold for Walker, the Spurs might have 15M in space, maybe 20M. They have Poeltl at C who is arguably better than Nurkic.; and they have Zach. At guard they have all-star Murray, Keldon Johnson, Lonnie walker, Josh Richardson, Joshua Primo, and Devin Vassell
Nurkic is a traditional C at the time when the NBA is abandoning traditional C's and their vulnerability in the PnR. They have almost hit the dime-a-dozen value. Nurkic also has a very extensive and worrisome injury history. A team would have to want an often-injured C as their starting C and I can't see any of the teams with cap-space going for Nurk in that role. Especially not for 15M/year
Simons has lots of hype among Blazer fans but I question how far that hype has penetrated into NBA front offices. I don't believe a 25 game sample size in a 4th season player on a crappy team is going to generate any giant contract offers.
I don't believe either of Portland's free agents will generate the 2022 version of the Crabbe offer sheet. There are too many flaws in the games of the pair. Obviously, as I said, all it would take is one GM to blow my theory out of the water. But I think the Blazers need to really do a good jobe of assigning value here. They've seen Nurkic in street clothes too often, and they have lived thru overpaying CJ so they have templates for what not to do