Heat olive oil in a large Dutch oven over medium-high heat.
Add chicken cubes and sauté until browned and internal temperature reaches 165°F (74°C), approximately 6 minutes; remove chicken and set aside.
In the same pot, sauté diced onion and minced garlic until translucent, approximately 3 minutes.
Stir in red pepper flakes, smoked paprika, salt, and pepper to bloom the spices.
Pour in chicken broth and bring to a boil.
Add linguine pasta to the boiling broth, ensuring all strands are submerged.
Reduce heat to medium and simmer, stirring frequently to prevent sticking, for 9 to 11 minutes or until pasta is al dente and liquid is reduced by half.
Reduce heat to low; stir in heavy cream and Parmesan cheese, whisking continuously until the sauce emulsifies and thickens.
Fold in the cooked chicken and baby spinach, stirring until the spinach is wilted.
Garnish with fresh parsley and serve immediately.