Palmer's languid style disguises a pressure-proofed temperament, as proved at Euro 2024.
Upson said: "One of his biggest assets, and this is absolutely not a derogatory remark, is that he doesn't think. He just does what he does. He's not going to tighten up.
"We saw the perfect example in the Euro 2024 final. He does it all naturally and that is very powerful in moments of high pressure, which England will endure at some point at the World Cup.
"I don't know if there are many better than Palmer in that respect."
Nevin insists no-one should be fooled by Palmer's perceived casual style.
"There are plenty of different ways to play football," he says. "Just because the veins in your forehead are not permanently popping out, or you're not shaking your fist at people for 90 minutes, doesn't mean you're not fully engaged. You can still be cool and incredibly competitive.
"He looks like he just cruises along, but look at his numbers, his impact.
"Cole Palmer has got a bit of everything. He's got brilliant dribbling ability. He's amazing in tight spaces surrounded by two or three players, creating more space when there doesn't seem to be any.
"At his very best, I think Palmer's world class. He would definitely in my squad if all things are equal, then I'd be very tempted to start him.
"He just needs to put together a two or three-month period at his best, then I can't imagine Tuchel not taking him."