Preheat oven to 400 degrees F. Line a large baking sheet with parchment paper.
In a large mixing bowl, gently toss shrimp with 1 tablespoon olive oil, salt and pepper. Transfer shrimp to lined baking sheet, spreading them out into a single layer. Place baking sheet in the oven a roast until shrimp are just pink, firm and cooked through- approximately 6 minutes. Remove from the oven and allow shrimp to cool. Chop shrimp into bite size pieces.
Reduce oven temperature to 350 degrees F and spray a 9x13 baking dish with nonstick cooking spray.
Heat a large skillet or Dutch oven over medium high heat and add remaining tablespoon of oil. Add onion and garlic and stir. Cook the onions and garlic until the onions are translucent and starting to soften, approximately 5 minutes (stirring often). Add the mushrooms, cabbage, carrots, spinach, chopped chipotle peppers, adobo sauce, oregano, parsley and cayenne. Cook everything together, stirring occasionally, until the spinach has wilted, approximately 2-3 minutes. Carefully add shrimp to the skillet and mix everything together.
To make the jalapeño cream sauce- heat a large saucepan over medium heat. Add butter. When butter has melted, whisk in the flour until lightly brown, only 1-2 minutes. Whisking constantly, slowly whisk in the chicken stock and cook until completely incorporated (do this slowly and with constant stirring; this should insure that no clumps form). Stir in the sour cream, followed by the jalapeños and green enchilada sauce. Simmer on medium low until the sauce has thickened, approximately 2 minutes. Season with garlic powder, salt and pepper. Remove from heat and gently stir in the fresh chopped cilantro.
Assemble the enchiladas- Place a tortilla on a large flat surface. Spoon 1/3-1/2 cup of the shrimp mixture into the center and sprinkle the top with shredded cheese. Roll up the tortilla and transfer to the prepared baking dish, placing it seam side down. Repeat this process with the remaining tortillas and shrimp mixture until entire shrimp mixture has been used.
Pour half the jalapeño cream sauce evenly over the top of the enchiladas. Bake in the oven, covered, for approximately 20-25 minutes, or until golden and bubbly. Remove from the oven and serve with the remaining jalapeño cream sauce, fresh chopped cilantro and hot sauce (if desired).