To be able to type Nudi5 on Facebook, a recommended Kannada Keyboard layout is required. Luckily, there are plenty applications out there that can fulfill this job.
For example, the Kannada Phonetic keyboard from Branah allows you to type Nudi5 and post to Facebook in case you have a different keyboard layout.
Visit the following link to start typing: https://www.branah.com/kannadaphonetic