Well if any left winger were to argue that merely believing capitalism with a touch of regulation works is all that makes you a Nazi, I’d be inclined to disagree with them even as a liberal progressive.
For me it’s believing that what you read, what you are taught, who you love/marry, how you practice art, what happens between you and a doctor, and where you were born that needs to be policed, controlled, and punished is what makes a Nazi. I honestly don’t think a genuine American conservative would care about any of that.