One must be careful in equating velocity to pressure as there is no direct correlation except with larger amounts of the same powder. You really have no idea what the pressure is of the round by it simply being marked with the NATO cross. IMO the higher pressure and velocity statements regarding this ammo is common sales puffery.
According to the published ballistics for the ammo at Midway.com the velocity of the Winchester NATO 124gr FMJ is only 1,140 fps which in itself doesn't indicate a +P level as other Winchester loads of the same bullet weight have higher velocities at 1,180 fps and are "standard pressure" loads.
There is a NATO spec for 9mm but many countries in NATO load their rounds differently or have a variety of loads some of which can be much higher pressure than what NATO (the organization) specifies.
"The NATO standard specification calls for a 7.45 g full-jacketed bullet loaded to deliver a velocity of 396m/s, mean pressure to be 2050 kg/cm2* and the Accuracy Figure ot Merit 76 mm at 50 m. " Source is Janes Small Arms and Ammunition.
If you do the metric to English conversions of the specs you find that it is 7.45g = 115 gr, 396m/s =1,299 fps, 2050 kg/cm^2 = 29157.85 PSI. Since SAAMI maximum standard pressure for the 9mm is 35,000 psi NATO specifications are well below SAAMI. The velocity is rather high for a handgun but the barrel length to be used is unspecified and likely sub MG length maybe 2X handgun length or more.