Preheat your oven to 350°F (175°C).
In a large skillet, heat the olive oil over medium heat. Add the shrimp, garlic powder, onion powder, chili powder, salt, and black pepper. Cook for about 3-4 minutes, or until the shrimp are pink and cooked through. Remove from heat and let cool slightly.
In a mixing bowl, combine the cream cheese, 1/2 cup of the shredded Monterey Jack cheese, and 1/2 cup of the sour cream. Stir until smooth.
Add the cooked shrimp to the cream cheese mixture and fold gently to combine.
Spread 1/2 cup of salsa verde evenly on the bottom of a 9x13 inch baking dish.
Take a tortilla, spoon about 1/4 cup of the shrimp mixture into the center, and roll it up tightly. Place the rolled tortilla seam-side down in the baking dish. Repeat with the remaining tortillas and shrimp mixture.
Once all tortillas are in the dish, pour the remaining salsa verde over the top. Spread the remaining sour cream evenly over the enchiladas, then sprinkle with the remaining Monterey Jack cheese.
Cover the dish with aluminum foil and bake for 20 minutes. Remove the foil and bake for an additional 10-15 minutes, or until the cheese is bubbly and golden.
Remove from the oven and let cool for a few minutes. Garnish with chopped cilantro and sliced green onions before serving.