how can i add videos to ipod nano 7th generation? what are the compatible formats?

You can configure movies/videos to sync to the Nano via its Movies configuration tab/pane in iTunes. See the appropriate section in this article for more information.

iTunes: Syncing media content to iPod

And regarding compatible formats...

From this page: http://store.apple.com/us/browse/home/shop_ipod/family/ipod_nano

• H.264 video: 720 by 576 pixels, 30 frames per second; Baseline, Main, and High-Profile level 3.0 with AAC-LC audio up to 256 Kbps; 48kHz; stereo audio in .m4v, .mp4, and .mov file formats
• MPEG-4 video: up to 2.5 Mbps, 720 by 576 pixels, 30 frames per second; Simple Profile with AAC-LC audio up to 256 Kbps; 48kHz; stereo audio in .m4v, .mp4, and .mov file formats

B-rock

I've seen alot of questions like this on the internet but I have found only one way to get the .avi's on my computer to be read on my iPod: This tutorial. Now everything cannot be perfect... It's in french. But it's better than nothing, and pretty clear.

Hope I helped you.

Here's a way it's fast and simple you can do. Here is the link P.S it's my video Link: https://www.youtube.com/watch?v=5wGq1IG7o08&feature=youtu.be Hope It helps! Works with most video websites.