Set aside two large baking sheets.
Into a large microwave-safe bowl, pour the pretzels.
In a small bowl, whisk together the oil, sugar, and pumpkin pie spice until well combined. Drizzle mixture over pretzels and toss to coat.
Microwave the pretzels for 60 seconds. Stir well and microwave again, another 45 seconds. Pour the pretzels out onto two large baking sheets. Sprinkle generously with cinnamon sugar while still hot.
Melt the white chocolate (over low heat or in the microwave in 30 second increments, stirring each time, being careful not to burn). Drizzle white chocolate over the pretzels. Then, sprinkle the pretzels with sprinkles, if using.
Allow white chocolate to set and cool completely. Break apart and store in bags or airtight containers.