Clarifying Authority over Nicotine Act of 2021 This bill expands the statutory authority of the Food and Drug Administration (FDA) to regulate tobacco products by amending the definition of such products. Currently, the statute defines tobacco products as products intended for human consumption that are made or derived from tobacco. The bill amends the definition to also include products that contain nicotine from any source, excluding foods that only contain trace amounts of naturally occurring nicotine. Beginning 30 days after this bill's enactment, existing laws, regulations, and related FDA guidance pertaining to tobacco products shall apply to tobacco products as defined under this bill.