Coat a rimmed baking sheet with olive oil mister or cooking spray. Place squash on sheet, spray with additional olive oil, and season with salt and pepper. Roast for about 40 minutes, stirring halfway through, until tender and just beginning to brown on edges.
While squash is baking, start brown butter. Heat a small skillet over medium heat. Add butter and whisk. Once butter has melted, add sage. Continue to whisk until butter begins to turn brown, about 5 minutes. When butter has browned, remove from heat immediately.
Transfer squash to large bowl; gently toss with brown butter and sage.