His army seems very limited, is it really just a single massive block with three war machines?
He is spending a lot to kill magic, let him waste those points, don't take any magic! You don't have to worry about his offensive magic and yours can't get through.
See attached list, this can be tuned considerably but it will soon get him off the anti-magic big block. Run the three cham units up to the three warmachines and try to shoot them to death, only charging if you get him down to one model or he is grapeshotting you to death.
Shoot his big block with sallies and skirmishers, keep your saurus block out of the way behind terrain (make some wall terrain!) and consider putting a big hill in the middle of the battlefield. If chams haven't killed cannon consider moving a skirmisher unit to help, then once main block reduced to managable size consider bringing out saurus unit to challenge it but keep shooting it up in the meantime.
Sallies should stay out of charge arc, skirmishers should stay out of charge arc or flee, skinks can normal move as far as he can march. Saurus should also consider deploying 1 rank deep if sufficient cover not available so cannon do max 1 wound per cannon per turn, reform to 12 wide when big unit gets close to maximise attacks. Str 4 AP will eliminate his 5+ AS but you will want to have reduced him to under 3 ranks to reduce value of his horde status.
Following army is designed solely v my impression of his army, you can lose a unit of skinks and distribute points amongst chams and saurus. LM armies are best over 2500 so get more troops!
1500 Pts - Lizardmen Roster - LM8 1500 no magic
Saurus Oldblood (General) Obsidian Blade, Armour of Destiny
Saurus Scar-Veteran, (Battle Standard Bearer); Great Weapon; Light Armour; Shield; Razor Standard
3 Salamander Hunting Pack, 9 Skink Handlers
2 Salamander Hunting Pack, 6 Skink Handlers
5 Chameleon Skinks,
5 Chameleon Skinks,
5 Chameleon Skinks,
10 Skink Skirmishers, Blowpipe
10 Skink Skirmishers, Blowpipe
11 Skink Skirmishers, Javelin & Shield
10 Skink Skirmishers, Javelin & Shield
18 Saurus Warriors, Musician Standard Bearer; Hand Weapon; Shield;
Composition Report:
Points of Lords: 251 (0 - 375)
Points of Heroes: 169 (0 - 375)
Points of Core: 524 (375 - Unlimited)
Points of Special: 180 (0 - 750)
Points of Rare: 375 (0 - 375)
Total Roster Cost: 1499