I haven't heard rumors of a new codex yet, but I don't have my ear to the ground these days. What's your source? You need a codex to play the game, so either borrow one from some kind person or buy one if you've just heard 'Tyranids SHOULD have a new codex soon'. Like I said, I'm a bit out of the know at the minute.
The advice for Nids doesn't change. It hasn't since Leviathan, it won't till a new codex. Flyrants, Mawlocs, Mucoloid Spores, Malanthrope/Venomthrope. Spam S6 Devourers whenever possible. Cry when Grav or Plasma wrecks you. Cry when D wrecks you. Take small bugs ONLY if you're using a metric poopton with the only MCs as Flyrants. Avoid most of the codex. It's the same generic advice you can find on any of the threads in this category. Nids don't have many options these days.
Now, if you have a specific theme in mind that isn't ever going to see play against top tier lists and factions, we can work with that. However, without a set path in mind and a lack of caring about competing, you will just get the same boring guideline. Flyrants, Flyrants and another pair of Flyrants, all built exactly the same... *Yawn*
As you can see, I'm a little bit jaded since my favorite army just can't play in my local meta... I'm bored of struggling to survive and casual games are too few and far between now. But, all hope is not lost. Tyranids can be a lot of fun if you have like-minded folks to play against.