Toss together Chex, pretzels, nuts, and oyster crackers in a large mixing bowl. Combine vegetable oil and melted butter in a small bowl and add garlic powder, onion powder, dill weed, parsley and salt. Stir to combine well. Pour over snack mix and toss until well combined. Transfer to a large rimmed baking sheet and bake for approximately 30 to 35 minutes, gently stirring about half way through the cooking time. Remove from oven when oyster crackers appear toasted and light golden brown. Taste and season with additional salt if desired.