I know nothing about this module in general, but your entry doesn’t seem to conform to the norm. You could try this:
{
module: 'MMM-OnScreenMenu',
position: 'bottom_right',
/* Valid positions: 'top_right', 'top_left', 'bottom_right', 'bottom_left' */
config: {
touchMode: true,
enableKeyboard: true,
}
},