Pre-heat grill or broiler.
In a large skillet, over medium-high heat, saute butter, mushrooms and green onions until tender.
Stir in spinach and pecans; saute until spinach is wilted; add salt and pepper, to taste; remove from heat; keep warm.
Sprinkle chicken with seasoning; along with a bit of kosher salt, and allow to rest for about 10 minutes before broiling.
Grill, covered, on an oiled grill rack, over medium heat, or broil 4-inches from heat on a greased broiler pan, until a thermometer reads 165°F; 4 -5 minutes per side.