In a large bowl, whisk together the flour, baking soda, baking powder, salt, cinnamon, and nutmeg.
In another large bowl, use an electric mixer (or stand mixer fitted with a whisk) to cream the butter and sugar together. Mix in the eggs and vanilla.
Turn the mixer down to low and slowly add the flour mixture to the butter mixture. Stop and use a spatula to scrape the sides as needed. Fold in the oats.
Divide the dough in half between the two bowls. Fold the raisins into one half and the chocolate chips into the other half.
Spoon out the cookie dough about 3 inches apart onto an ungreased baking sheet (lined with parchment, if desired) and bake one sheet at a time until golden brown, 8 to 12 minutes. Alternatively, you can bake both sheets at the same time on convection.