Yes, you can :)
You can take any reporter that is
1) efficiently quanched by the quancher (BHQs are quite promiscous) and
2) efficiently excited and detected by your intrument (depending on laser/LED wavelength and filters/detectors)
NED has the Excitation peak at 550nm, FAM at 495: check if FAM will be excited.
NED has the Emmission peak at 570nm, FAM at 515: check if FAM will be detected.
If both answers are "yes" then there is nothing to say against using FAM intead of NED. Most real-time cyclers should have the appropriate optics to measure FAM, so this shouldn't be a problem.
Note that Cy3 has the same spectral properties like NED (in case you are just looking for a possibly cheaper alternative). And instead of FAM you might consider HEX, JOE, VIC, or TMR, that have spectral properties that are more similar to NED than those of FAM.