The View supports MP3, protected and unprotected WMA and WAV. It can play MPEG4, WMV and H.264 video at 30fps and also features FM radio.
The player also features a voice recorder, microSD/SDHC expansion slot and a lithium polymer battery which should give you 35 hours of audio or seven hours of video.
The Sansa View is available in 8GB and 16GB for $149.99 and $199.99, respectively. So basically, for the same price as the iPod nano you get twice as much storage capacity.