Mix olive oil, garlic powder, onion powder, chili powder, Cajun seasoning, and sea salt in a large resealable bag. Add potatoes and toss to evenly coat with seasoned oil. Spread coated potatoes in 1 layer onto a baking sheet.
Bake in the preheated oven for 35 minutes. Stir potatoes with a spatula and continue cooking until crisp, about 10 more minutes.