Nikon Japan's website as has been posted, have MTF charts.
Also keep in mind Canon and Nikon's MTFs are incommensurable because they each use a different set of conditions in their chart (Canon 'cheats').
To be honest, I don't think the lenses are the limit to resolution in current day digital tech - it's the sensors. I find there is a fairly big loss of resolving power with CMOS imagers, from the flagship Canon products and admittedly also from the D2X. CCDs from the D70/D100, Fuji S2/S3 seems to have better resolution per given megapixel. I put it down to overly aggresive noise reduction algorithms implemented in CMOS cams, as they are inherently a more noisy technology - but which seems to be the direction digital imaging technology is heading.
While you could not find a stronger opponent of Canon on these forums than myself (and my strong opinions are backed by facts), I do believe they are onto something BIG for next year's flagship 1 series
models... if you're prepared to wait that long. They've adopted Foveon-like technology to individualise 3 colour capture. But know Canon the first release will be rushed and it'll take 2-3 iterations (that's about 6 months from first release) to get it right.