Just buy a cheap plastic Chess set with bigger pieces?
Use black pieces.
Pawns= Minions
Knights = Lurkers/Rogues
Bishops = Artillery/Controllers
Rooks = Soldiers/Brutes/Defenders
Queen = Either second most powerful creature, or Boss Spellcaster Type
King = Most powerful creature, or Boss Physical Threat Type
Can be subbed in whenever necessary. Especially for minions, which are going down in one hit anyway, so it's not a horrible thing if they're represented by a dumb pawn.
For a starter mini set, white pieces can sub in for all the pcs (Rooks = Defenders, Knights = Rogues, Bishops = Clerics, King = Warlord, Queen = Warlock/Wizard, etc.)