You’re correct. Fives states - Arkansas, Louisiana, Mississippi, Alabama, and Georgia - went for Wallace. He got about 9.9 million votes. Likely, most of those would have gone to Nixon had Wallace not run.
The problem with counter-factuals like “what if Wallace hadn’t run” is you just don’t know. Yeah, purely on the face of it, his numbers probably would have gone to Nixon. But the dynamic of the campaign might have played out differently, and then who knows?
It’s like the Ross Perot candidacy. Clinton-people say that had Perot not run, his votes would have gone to Clinton. Really?