Surgery may now be required to rectify the damage, however, potentially ruling Nowell out for the next eight weeks, with the first of England's three matches taking place on November 11.
"He's got a couple of fractures in the top of his check and eye socket," Exeter director of rugby Rob Baxter told BBC Sport. "It's still a little early to write him off for the whole of the autumn internationals, that's something we're going to have to assess in the next week or so.
"It's always a blow when you lose good players, that's why you put a squad of people together, but we're big believers here that if one person picks up an injury it's an opportunity for someone else."
Nowell will definitely sit out Exeter's games against Glasgow Warriors and Montpellier in the European Champions Cup, as well as the league clash against Sale Sharks.