Well I am probably stating it poorly. He's good at separation. But, Waddle has elite speed like Jakeem Grant and Albert Wilson, so some CB's just play off them a lot, providing constant separation. And like those guys Waddle also has great acceleration, so out of his breaks he generates separation even if the CB is close. Simliarly, Devonta Smith's biggest strength is his elusiveness, which includes his burst to create separation and running good routes to set up generating that separation. One reason those guys were recruited to Alabama is that they're both truly exceptional at generating separation. So, it's not that Chase is not a good separater, he is. But, when compared to Waddle and Smith, Chase is not quite as bursty to get the same level and consistency of separation as those guys.
Chase is a lot better than Davante Parker or Preston Williams at generating separation. I think I should have stated that more clearly. My bad.