EPDM and nitrile turn up in a large share of industrial rubber parts, and they fail in opposite places. Before comparing datasheets, answer one question: does the part see petroleum oil or fuel, or does it see weather, ozone, and hot water?
Nitrile for oil and fuel
Nitrile resists swelling in petroleum oils and fuels. For seals, gaskets, and fuel-system parts it is usually the starting point, and it is inexpensive. Its weakness is outdoors. Ozone attacks the double bonds in its backbone, and a stressed nitrile part left in weather will crack eventually.
EPDM for weather, steam, and hot water
EPDM has a saturated backbone, so ozone has nothing to attack. That makes it the normal choice for outdoor seals, HVAC parts, and hot water or steam service. Put it in oil and it swells badly. No formulation trick fixes that.
When the answer is neither
Some parts see oil, heat, and weather together. Splitting the difference between two general-purpose polymers usually produces a part that is mediocre at both. HNBR and FKM exist for that case, and they cost more for a reason.
If your application straddles both, send us the fluid, the temperature range, and the duty cycle. We would rather scope it than have you pick from a chart.