Preheat the oven to 375 degrees.
Slice the onion and bell peppers and place in a large mixing bowl. Rinse shrimp under cold water and pat dry with a paper towel or cloth and add to a separate bowl.
In a small bowl, mix together spices (chili powder, cumin, oregano, paprika, salt, pepper). Add 1/2 the spices and olive oil over the shrimp and the other half over the onions and peppers and coat well.
On a large baking tray with parchment paper, lay out peppers and onions so they do not overlap on top of each other. Cook for 15 minutes then add in the shrimp to the baking tray and flip the peppers and onions. Cook for 8-10 minutes or until shrimp have turned pink (you can flip shrimp after 4 minutes and add the tortillas to the pan).
Add tortillas onto the baking pan 4 minutes before the vegetables and shrimp are done, and flip after about 2 minutes so both sides get crispy (this could be a little bit longer depending on the type of tortilla you are using).
Enjoy with a squeeze of lime and some sliced avocado!