Bring a large pot of salted water to a boil and cook the spinach ricotta tortellini according to the package directions, then drain and set aside.
Season the chicken breast evenly with the sea salt and black pepper.
Heat the olive oil in a large skillet over medium-high heat and sear the chicken for about 6 minutes per side until golden brown and cooked through.
Remove the chicken from the skillet, let it rest for a few minutes, and then slice it into thin strips.
In the same skillet, melt the unsalted butter over medium heat, whisking frequently until it begins to foam, turns a deep amber color, and releases a nutty aroma.
Stir the chopped fresh sage and baby spinach into the brown butter until the leaves are just wilted.
Add the cooked tortellini and sliced chicken back into the skillet, tossing gently to coat every piece in the fragrant brown butter sauce.
Drizzle with lemon juice and sprinkle with parmesan cheese before serving warm.