Elite guardsmen wrote:
We'll I was thinking of starting tyranids and I think I'll buy swarm force but I don't know what to add to it to make it a good 1250 list and I don't have to use everything in the box just tell me some good units thanks
You'll need an
HQ, and you'll be short of Synapse. I suggest a Hive Tyrant box, and a box of Warriors. Then you can build a decent force using basicly every figure, Nids are cool that way.

As long as you stick to "vanilla" (few to no upgrades) Nids can spam figures like nobodies business.
So say...
HQ: Winged Dakka'rant Wings,
TL Brain Leeches x2 230, 240 with a Thorax Hive of Electro bugs (not nessisary, but recommended)
Troops: Warriors x3 Cannon 100
Troops: Termigants, x 20 80
Troops: Termigants, x20 80
Troops: Hormigaunts x15 75
Troops: Hormigaunts x15 75
Gargoyles: x10 60 points
Carnifex:
TL Brain Leeches x2 150
That runs around 860...

So you can trim to 750, or upgrade to get 1000+ etc...

For example, if you toss Toxin Sacks on the Hormies, you add 45 per Brood to your cost, that puts you at 950, buy a Zoathrope, or a Venothrope, and you get 1000.
You can also model a portion of you Termigants as having Devourers (Devilgaunts) this is a major upgrade in effectiveness, and a major upgrade in Price (literally twice as expensive

)( I modeled mine using Hormie figures and modding them to use Devourers)( that would give you 10 Devils to add to a Termie Brood(s)) ( 80 more points to build)
So as you can see its "easy" to spend up to higher build costs.
Good luck! And welcome to the Hive Mind!