Heat a large skillet over medium heat and add coconut oil. Cover the squash slices with salt and pepper, then add them to the skillet and cook until golden, about 5 minutes per side. If desired, you can add the brown sugar to help the squash caramelize. Heat a small saucepan over low heat and add the pecans. Toast until they are slightly golden and fragrant, stirring and shaking the pan as they toast, for about 5 minutes. Toss them with the pumpkin pie spice.