Preheat oven to 425º and prepare two baking sheets with parchment paper.
In a small bowl, whisk together olive oil, sweet chili sauce, sriracha, lime juice, tamari, and garlic.
On a large baking sheet, toss Brussels sprouts in sauce until fully coated. Season generously with salt and pepper.
Roast until slightly charred and tender, 30 to 35 minutes.
Meanwhile, pulse the cereal in a food processor until crushed to look like panko bread crumbs. Remove and set aside. Add in the cashews and pulse until they reach crumbs.
Add the olive oil to a pan over medium heat along with the crushed cereal and cashews. Toast until just golden brown, about 3-4 minutes.
Top the crispy brussels sprouts with the "panko" nut topping and sprinkle with fleur de sel. Enjoy!