nutshell

ace, dab, dash, driblet, drop, fraction, haet [chiefly Scottish], halfpenny, ha'penny, iota, jot, kenning [chiefly Scottish], lick, minim, mite, modicum, ounce, pinch, shred, smatter, smidgen (also smidgeon), spot, strain, streak, suspicion, taste, touch, trace, whisper, whit

atom, bit, crumb, dribble, fleck, flyspeck, grain, granule, molecule, morsel, mote, nubbin, nugget, particle, patch, scrap, scruple, snip, snippet, speck, tittle

bite, mouthful, nibble, tidbit (also titbit)

fragment, part, portion, section

chip, flake, shard, shiver, sliver, splinter

clipping, paring, shaving

smithereens