I thought I'd kick off some tactical discussions about the new codex - tentatively under the [Hivemind] heading (to maybe make them easier to find?) to help us get the most from the codex and win more games!
This topic will cover general secodnaries for Tyranids, and also their new specific secondaries - let us know what you're taking, how well it's working, and how you're building your army to maximise these secondaries.
Tyranids Specific Secondaries Summary:
Synaptic Insignt (Direct copy from GT: Nachmund) - No Mercy, No Respite
Kill 4, 3+ wound models in your turn with synapse creatures to get 3VP, max 12.
Cranial Feasting - Purge The Enemy
Kill characters and unit champions in melee with tentacle face beasties
Spore Nodes - Shadow Operations
Perform action with a Troops Unit within 6" of opposing DZ, 4VP each time.
Spore Nodes: Of these, this would seem to be the easiest to complete, with the others requiring specialised units (or luck) and to kill stuff in combat. Nodes competes with things like banners, nachmund data and homers. For us, this is strictly a better homers, and reduces the ramdom roll for nachmund data. If you were doing either of these, you can probably switch to nodes and have a lot of success!
Feasting - to max this you need to kill the warlord in melee, get a reroll, then kill eight (yes, eight!) other characters or unit champions - all with tentacle units/genestealers. This is a very hard ask for me - the only instance I can think of picking this over assassinate would be if my opponent was fielding MSU (10+ weak units that all need to be in buffing range) and I was running a genestealer themed army.
Synaptic Insight - If you have a shedload of synapse, then this might be doable, though it's also really dependant on your opponent's army, which is the downfall. If 2W models counted, but you needed to kill more, this would be ok, but against marines, unless they're running a pure gravis army, you'll struggle to score. If you're facing a buggy list, for example, you need to kill 2 buggys get get 4 synaptic tally, which is 4VP, which is better than the 2VP you get via Bring It Down...however BID can be completed by anything. How often are your synapse creatures going to be killing large models? Maybe this will change with the new heavy venom cannon, and a psychic heavy army might do wonders here!