Having the most nubs or small lumps.
The word nubbliest makes people think of things that are bumpy or rough.
Examples:
The blanket is the nubbliest one I have.
This fabric is nubbliest of all.
The road is the nubbliest I've ever seen.
Her sweater is the nubbliest thing I've ever felt!
The rock was the nubbliest rock in the whole world.
The cat's tongue is the nubbliest thing when it licks you.