Pat the chicken dry. Mix the 1 1/2 teaspoons chili powder, 1 teaspoon ground cumin, 1 teaspoon kosher salt, and 1/2 teaspoon ground black pepper, then season both sides of the chicken and rub to coat.

Set the Instant Pot to SAUTE. Add the 1 tablespoon extra virgin olive oil and heat until shimmering. Add the chicken breasts in a single layer and sear 2–3 minutes per side, until browned (they do not need to be cooked through). Remove the chicken to a plate and set aside.

Turn the Instant Pot OFF. Pour the 1/2 cup water into the pot and scrape up any browned bits with a wooden spoon or rubber spatula. Return the chicken to the pot and pour 1/2 cup of the enchilada sauce over the chicken (from the total 2 1/2 cups; reserve the remaining sauce). Lock the lid and cook on MANUAL/HIGH pressure for 8 minutes.

While the Instant Pot comes to pressure/cooks, place racks in the upper and lower thirds of the oven and preheat to 350°F. Arrange the 12 corn tortillas in a single layer on two baking sheets. Use the 3 tablespoons canola oil (or nonstick cooking spray) to lightly brush or spray both sides of the tortillas.

When the 8-minute cook time ends, perform an immediate quick release (vent). Carefully open the lid and check the internal temperature of the chicken (should be 165°F). If under 165°F, either reseal and cook 1–2 more minutes under pressure or let the chicken rest covered for a few minutes until it reaches 165°F.

Remove the chicken to a plate. Set the Instant Pot to SAUTE and simmer the cooking liquid, stirring occasionally, until reduced by about half, about 5 minutes.

While the liquid reduces, warm the tortillas: bake on the upper and lower racks until the tortillas are warm and pliable, about 3 minutes, then flip the tortillas and bake another 2–3 minutes. Stack the warmed tortillas and cover to keep warm. Move one oven rack to the center and leave the oven on.

Shred the cooked chicken with two forks on the plate, or return the breasts to the Instant Pot after the sauce has thickened and shred directly in the pot with a hand mixer on low. Return the shredded chicken to the pot and stir to coat with the reduced sauce.

Stir into the shredded chicken: half of the chopped green onions, the 1/2 cup nonfat plain Greek yogurt, and 3/4 cup of the shredded Monterey Jack (or cheddar jack) cheese.

Spoon about 1/2 cup of the reserved enchilada sauce into a 9x13-inch baking dish and spread into a thin, even layer.

Place a heaping 1/4 cup of the chicken filling onto each tortilla, roll tightly, and place seam-side down in the baking dish in a row down the center. Repeat with all 12 tortillas (tuck any extra rolls along the sides if needed).

Pour the remaining 1 1/2 cups of enchilada sauce evenly over the rolled tortillas. Sprinkle the remaining 3/4 cup shredded cheese over the top.

Bake in the 350°F oven until warmed through and the cheese is melted and bubbly, about 15 minutes.

Remove from the oven, sprinkle with the remaining chopped green onions, and serve hot with additional Greek yogurt and desired toppings (chopped fresh cilantro, sliced avocado, sliced jalapeno).