What is the biggest you can print Nikon d700 photos?

What is the biggest you can print Nikon d700 photos without it losing quality?

Captured in RAW with a sharp lens, correctly resampling in Photoshop, and printing on matte paper, you could easily do a 30X40" print, as long as your viewing distance was at least 4 feet.

If you were to print on canvas you should be able to print at least 40X80".

Besides the camera resolution, which in your case is roughly 3, 000 X 4, 000 pixels, the most important factors in determining printing size are

-media type (glossy, matte, canvas, etc… )
-Viewing distance (you can print a 200 foot wide billboard with your camera if you are far enough away.)
-software. How you resample an image has a lot to do with how large you can print it.

If it's an uncropped image, I'd go for 24 x 36 poster print. As stated above, it can depend on quite a few factors, the biggest of which is if the file you're using has been cropped at all. Shooting at very high ISO can limit the size you can print out as well.