In the very beginning, you should keep in mind or confirm which file format supported by Kindle Fire or Nook Tablet.

Kindle Fire can accept Kindle (AZW), TXT, PDF, unprotected MOBI, PRC natively, Audible (Audible Enhanced (AA, AAX)), DOC, DOCX, JPEG, GIF, PNG, BMP, non-DRM AAC, MP3, MIDI, OGG, WAV, MP4, VP8.

Nook Tablet: MP4, or Adobe Flash Player format, 3GP, 3G2 MKV, WEBM (Video Codecs: H.264, MPEG-4, H.263, VP8);MP3, MP4, AAC, AMR, WAV, OGG (Audio Codecs MP3, AAC, AMR, LPCM, OGG Vorbis)

From the above formats list, you can easily find that WMV file format is excluded. In order to watch WMV content on these two tablets, you may need a third-party programs-Doremisoft WMV Converter or Mac WMV Converter.

It offers you an easy way to batch convert WMV to Kindle Fire MP4, or WMV to Nook Tablet MP4/MKV,etc. Meanwhile, it has many features to help you edit, trim,cut, split, merge your video clips, and allows you to adjust video and audio parameters like bit rate, etc.

Note: If you are using Mac PC, rather than Windows OS, you can refer to Mac WMV Converter to convert WMV to Nook Tablet on Mac.

With the Mac WMV Converter, you do more these jobs as well:

1. Convert WMV to MP4, MOV, MKV, AVI, etc. on Mac (Lion OSX included)
2. Convert HD movies like M2TS, MTS, HD MKV, 1080P movies or SD FLV, MKV, AVI, MOV, MPEG, etc. to WMV on Mac
3. convert WMV for further editing into iMovie, FCP or FCE
4. Extract audio from WMV to MP3, WAV, M4A, etc. on Mac