There are modern Vocoder out there in Electronica. I don't play with them, other to see if the hardware works. So, from what I can tell, you have synth processing and effects that that work on the voice or audio input, and then, it is mapped across the keyboard - you sing monotone and play the pitch on the keys.
But, the audio(MIC) is into a synth input and that jack is quite common, today. My first "own money" plug was a Alien Solo VST/i synth to try and make my guitar into a bass. hahaha. I knew I should buy a bass, but that costs money. UNIVIBE vst, MAYBE
If the vocal is nasally, it might be the Vocoder ?