If he wins the nomination, 15+ for sure. If he was able to successfully sell himself to the Democratic apparatus, he'd get at least 43% in the GE. The country is too polarized for him to lose in a true landslide.
What would him garnering 43% look like?
I'm not entirely sure, but if he's popular enough among Democratic voters to win the nomination in the first place, I imagine that he'd get at 187 EVs:
I don't think he'd do worse than the above map.
This is realistic. Any other states flipping wouod be a result of factors not inherent to Kanye West.