To begin with, Moto Ghotalo is more like a Rajasthani (and maybe to an extent Gujarati) version of what would be Mota Ghotala, or bada Ghotala in Khadi Boli Hindi. [For the uninitiated, Khadi boli is the dialect of Hindi that was spoken in the Western UP/Delhi areas and has in time found prominence in most places, including Film Industry.]
So, moto ghotalo, or bada ghotala would in English be 'big scam', or 'big scandal'. Mota is also the word for 'big' in Gujarati.
Update: In Gujarati, Ghotalo is used for mistake, and so, in Gujarati, Moto ghotalo would mean 'Big mistake.' Though this was a relatively small one. :D