It's not grease nipples, it's oil points. You get an oil can with a small round steel tip. The tip pushes the ball down and you then pump in some oil. I use Way oil in mine, #5 mobil if I remember right. Squirt it in the holes every few times the machine is used and also squirt it along the ways and run the tailstock and cross slide along the ways to spread it out and soak it in. Then I spray the the machine <unpainted surfaces of course> with motorkote, synthetic penetrating oil, comes in an aerosol type can. you can't have too much oil protection, just not enough.
those grizzly pics are exactly right. If you can find an all metal one with no plastic parts, even better. Those plastic ones tend to fall apart real fast. i got an old vintage aluminum one at a garage sale, it's dinged up but it works excellent and no doubt has pumped many gallons over the years.