Hi guys, i would like to know is there any vast differences between the three words? Can we use 'pood dai nit diaao/nit neung' like how we use 'pood dai nit noi' ?

Literally (and therefore somewhat roughly), นิดหน่อย nit noi means "a little bit", นิดหนึ่ง nit neung means "one bit", and นิดเดียว nit diao means "a single bit". So while they're sometimes interchangeable, I don't think you could use just any of them in the way you mention. Stick with poot dai nit noi.