So, I'm playing my first game as Lizardmen against Chaos Daemons next week, with a 1000 point limit. My army list is 2 x 18 Saurus with full command and hand weapons 12 skink skirmishers with javelin and shields Skink priest level 2 lore of beasts scar vet shield, armour of destiny and sword of striking 6 cold one rider's with full command any tactics?
Without knowing which of the dark god(s) your opponent is drawing from I'd recommend prioritizing demonic Heralds. At 1000 points your opponent won't be fielding any lords (unless he wants to field a Daemon Prince with no upgrades at all). Demonic heralds aren't very impressive statwise, but most of them have a locus upgrade which means they provide a buff to the unit they joined as long as they are alive.
It's not demon specific but I would recommend a tight deployment so your units can support each other. A unit by itself is a dead unit, unless the army is Nurgle based in which case your Skinks should be fast enough to stay out of enemy charge arcs with ease.