I made a pretty similar budget version of this deck and i have a few notes, Id put in 4 disposes in the sideboard for aetherworks marble , also since you aren't playing zombies,
Defiant Greatmaw can work better than plague beltcher if you have trouble removing counters quickly, it also allows you to drop copies of
exemplar of strength and
chandler initiate if you want a more mid-range deck,
soulstinger is great for comboing with
nest of scarabs, like if you play
soulstinger and
chandler initiate and dropping all the counters on
soulstinger, you can nerf a powerful creature and get 10 more scarabs, also consider
grasping dunes (you seem pretty set with land, so it can help landing you another snake or scarab for later game when you are set with mana. Also I am not sure what type of thing you are planning against, but you may want to switch
heroic intervention for
Destined // Lead (It can save one creature and creates a win condition )