Have you determined how the chuck fastens to the drill press... screws on, inserts into Morse Taper hole in spindle, or goes OVER a Jacobs Taper or other taper ON the spindle?
Look closely at the chuck for markings such as "MT2", meaning #2 Morse Taper or "JT3", meaning #3 Jacobs Taper, for example.
Once you have determined this, chucks are pretty generic.
I just dealt with this and bought keyless chucks for two drill presses from www.shars.com.
REASONABLE prices and FAST shipping.