[Nidus] is an underrated frame, and this is the best build for him I know. It's not a broken nuking build, but it's one that controls crowds with ease, boosts your primary weapon into absurdity, all the while making you the most durable frame on the battlefield. Here's how to play this build.

Abilities:
Use Larva and Virulence a lot. Gather groups of enemies into your larva and spam Virulence at them. Hitting 4 or more enemies will refund all energy cost while granting you extra crit chance on your primary weapon with [Teeming Virulence]. That crit chance comes out to be 370% normally, 450% with [Growing Power]. You'll be hitting red crits with your primary like it's nothing. Oh, and Molt Augmented will allow your Virulence damage to stack and reach close to 50,000-60,000. It won't be a lot against steel path enemies, but that extra crit weapon chance should be enough to dispatch them.

Lastly, Using the Larva and Virulence combo will gather mutation stacks for your other abilities. Use parasitic link on eximus or strong enemies to give them the damage you will be receiving and then some(redirected damage scales up with ability strength which is your main focus), and use Ravenous to heal you instantly if you get low on health, or to add extra oomf to your Virulence casts.

Weapons:
Come with a strong and fast attacking melee. Using Virulence to take out close enemies won't always be an option. Save it for groups. Fall back to melee attacks to pick off single enemies. Your secondary should be a status weapon with a different status than your primary and melee. Use your secondary weapon to apply status effects that cover for your other weapons' weakness. And, most importantly, bring a primary weapon with high crit damage multiplier. Remember, your crit chance will be reaching 450% at times, so capitalize on that with high multiplier, and high base damage. Incarnon weapons will do especially well.

Archon Shards:
Because you are using Arcane battery, and your focus is on Ability strength, use Crimson and Azure archon shards to boost ability strength, and armor. The added bonuses aren't game changing, but will be helpful for getting the highest numbers we can. then, use Coalescent shards to boost the damage of status effects that the weapons you are using have. This will boost your damage numbers and thus, your crit damage numbers when [Teeming Virulence] takes effect

End Result:
You will be tanky without trying, with options to make yourself even tankier. You will be the master of crowds, pulling them all in and widdling their health down to gain stacks and an absurd amount of crit chance. The only thing to be careful of is your energy consumption, but that can easily be managed by using your abilities on big crowds. Have fun being invincible!