Preheat oven to 425°F. Do not wash your mushrooms. If there is excess dirt you can wipe gently with a paper towel. Gently pop the stems out of the mushrooms and using a small ¼ teaspoon, scrape the inside gills and inner edge to create more room for the filling. In a large mixing bowl, mash up the sweet potato & chia bites with a fork into very small pieces. Add the vegan cheese, lemon juice, 1 tablespoon of olive oil, basil, oregano, and ground pepper and stir to combine well. Using the remaining 1/3 cup of olive oil, brush the bottoms of the mushrooms. Scoop the filling into the mushrooms with your hand and gently press it into a mound on top. It should be well compact and slightly mounding out of the mushroom. Place these on a large baking sheet, slightly spaced apart. Bake for 20 minutes. Serve immediately.