Not at all.
Having darker skin from a fake tan does not block UVA or UVB rays. To do this you need to use a proper broad-spectrum sunscreen. Some fake tanning products are rated with an SPF (sun protection factor), so if the SPF is above a 30 and if the product is certified broad-spectrum, you may be fine for limited exposure right after you apply it. Remember that all sunscreens need to be reapplied every few hours and after getting wet so don’t rely on your fake tan with sunscreen for long-term protection beyond what you would get with a regular sunscreen.