Mizoochicrash is the creator of one well-known WinMUGEN-era release. A 2012 MUGEN Free For All release thread explicitly credits the character as "By Mizoochicrash."
There is also another release archived under the author name w.h., indicating that multiple versions/conversions of Nonowa-san were made over the years.

From the sprite style you posted (the tiny chibi version with the pink bow), it appears to match the Mizoochicrash-era release that circulated during the WinMUGEN period around 2011–2012.