If you go back and look at Nico's HS races, he always looked like he was going all out from the gun as well. Lex and Leo seem to have more leg speed than Nico did tbh. I think they always run all out from the gun because that's the best way to run fast. Whatever talent they have, I don't think it's too far off from Nico, they just got a better start.
Will they match what he's done in college? Not many people have, but I honestly haven't seen any reason they wouldn't. The difference between their running and Nico's HS running is pretty remarkable. Not just the times, but their form is much cleaner. The strongest statement I'd make against the twins is that it seems like they're closer to their ceiling than Nico was in HS. Still, there's no way to know, and the twins could end up better than Nico when all's said and done.