Measure the mixed nuts and place them in a large microwave-safe glass or ceramic bowl. Spread them as evenly as possible so they heat more consistently. Avoid using metal containers or utensils in the microwave.
In a small bowl, combine the paprika, cumin, garlic powder, onion powder, salt, black pepper, and optional cayenne pepper. If you prefer a sweet-and-spicy flavor, add the brown sugar to the seasoning mixture.
Drizzle the olive oil or melted butter over the nuts. Sprinkle the seasoning mixture on top and stir thoroughly until the nuts are evenly coated. Use just enough oil to help the spices stick without making the nuts greasy.
Microwave on high for 1 minute, then carefully remove the bowl using oven mitts and stir well. Continue heating in 30-second intervals, stirring after each interval, until the nuts smell fragrant and are lightly toasted. This usually takes about 3–5 minutes in total, but microwave power and nut variety affect the timing.
Carefully transfer the hot nuts to a heat-safe plate or parchment-lined tray, spreading them into a single layer. Let them cool completely for 10–15 minutes. They will become firmer as they cool. Taste and adjust the seasoning if necessary, then serve or store in an airtight container.