Combine olive oil, lemon juice, mint, sage, thyme, salt, and pepper in a bowl; let marinate at least 2 hours. Blend oil mixture with the pine nuts using a blender or mortar and pestle until you have a creamy mixture. If the mixture is too dry, add more oil and lemon juice.
Preheat oven to 335 degrees F (170 degrees C).
Place trout on a baking sheet and stuff with the herb-pine nut mixture. Sprinkle onion, more oil, salt, and pepper on the outside of the trout.
Bake in the preheated oven until fish flakes easily with a fork, about 40 minutes. Pour white wine over trout and let it simmer in the hot pan.