I think it will be more competitive then most expect. He really has only lost to wrestlers in the UFC since the Jeremy Stephens KO loss like 7 years ago, and he has come a long long way since then.
Don't get me wrong, I am absolutely picking Pettis and I don't see the clear path to victory for Dos Anjos, but I think he can hang well enough on the feet to at least have a chance to try to work his grappling. That said, I honestly don't expect him to get past Pettis' guard. Pettis by decision IMO.
Man did Khabib ragdoll him though... give the man his shot already