With H I taste good.
With E I smell good.
With Y I snoop in the hood.
What am I... with HI?
You are:
the letters NOS.
With H I taste good.
Adding an 'H' to the end gives us NOSH, another word for food (which tastes good).
With E I smell good.
Adding 'E' gives NOSE, something which smells well.
With Y I snoop in the hood.
Adding 'Y' makes you NOSY, prying into what others are up to in the neighbourhood...
So, with HI you are:
NOSHI - a ceremonial origami fold, given as a gift to express 'good wishes'. (So thank you!)