Along the lines of the Wii audience.
Alot of people are suggesting they go head to head with the PS4/Xbone, which is about the stupidest possible strategy. Even if they launched at the same time Nintendo would have a hard time getting the COD/Madden audience based on their reputation, their franchises, and their staffing. Coming three years into the PS4's lifespan will make that challenge several times more difficult. Unless the NX is a true technical behemoth (like as strong in raw power as a mid-high end PC) then I don't see them stealing away many consumers from Microsonysoft.
Whether they can or not, they need to recapture the Wii audience, out of a matter of necessity. They either have to climb Mt Everest, or complete a successful manned mission to Mars. One is going to be incredibly challenging, but the other is nearly impossible.