believe it or not nascar does race at least 1 road coarse twice a year, and their can be arguments for both sides
i personally feel f1 takes more skill but not for the simple answer "well our guys turn left too" no, but i believe nascar only sees 5gs in a crash
where as an f1 driver can see 5gs lateral and negative just taking a turn on every lap, mashing the breaks into 5 negative Gs going through what pilots call "red out" (passing out because all the blood in your brain has shifted to your face) waking up in enough time to grab a gear and mash the throttle through a corner for 71 laps is impressive in anyones book
however the case for nascar is still strong, nascar races in the knifes edge of grip for every turn of every lap, they weigh more than an f1 car have less aero and mechanical grip than an F11 car, have far less sophisticated tires than an f1 car yet maintain a higher average and top speed than an f1 car, all the cars a pretty close to equal, there is no ferrari like team in nascar, you are never going to have a season where one driver wins half the season, in nascar a win is based on driver skill and a whole heap of luck,
but that said i don't think most of the nascar drivers would cut the mustard in F1 but i know of at least 5 that i think can