Wrong. Nixon was never indicted never mind convicted of anything.
Ford’s pardon was a blanket pardon that cover all of Nixon’s time in the presidency, all possible acts. The only thing Ford couldn’t pardon was future acts. I have read that the legal reasoning about that is that if the president could pardon for future crimes it would be tantamount to writing ad hoc legislation, which would exceed executive power (well unless you are Obama, of course).
Anyway, Obama certainly has the power to pardon Shrillary for unindicted past crimes. One hopes she doesn’t get off that way, but the presidential pardon power is very broad.
But if he did, the Congress would FINALLY act to stop him, by golly. / bitter sarc