Ok, let's have a go at this.
The Machamp set is fine as is, although perhaps Ice Punch or EQ instead of Knock Off (although this isn't something that needs to be done) for different coverage. However you can also run a Guts set w/ Assault Vest to catch out stray Toxics/Will-o-Wisps and get the Attack boost along with the SpDef boost. Of course replace DynamicPunch for either Close Combat (if you don't mind the stat drop), Cross Chop (If you do) or Low kKck (Because big beefy Steel mons).
The Pory-Z set I feel will needs to be Timid if scarfed, if you're running Modest then go 252 HP/252 SAtk.
Nidoqueen is fine as a bulky utility mon, however I feel that speedy hazard setters are the way to go in UU; IE get hazards out then switch away. This is why I use:
Uxie @ Leftovers
Ability: Levitate
EVs: 252 HP / 252 Spe / 4 SpDef
Jolly Nature
- Knock Off
- Magic Coat/Heal Bell/Thunder Wave
- Heal Bell/Thunder Wave/Memento
- Stealth Rock
Uxie's natural bulk along with an impressive Speed stat means Uxie can be a real nuisance in this tier. Knock Off is Knock Off - this allows a free moveslot for your Machamp too - Magic Coat I use primarily to stop hazards being set up but as you have Rapid Spin on Blastoise, feel free to either play Cleric with Heal Bell or Nuisance with Thunder Wave. Stealth Rock is something that can be set up fast, rather than running the risk of being one-shotted before you even set them up; Memento is a nice little niche to sac Uxie off when it's about to die (similar logic to Explosion Azelf). Very good at putting a stop to some of the more menacing setup sweepers you'll see.
Flygon set is ample enough, although perhaps switch Roost for Stone Edge, as EdgeQuake is very good for coverage (or even Ice/Fire Punch if you're feeling zesty)
Regarding your Jirachi set, I'm not too sure what you're looking to do; I'd suggest either a mixed attacker set or essentially a pivot set (nice avoiding EQs/resisting Fire with Flygon):
Jirachi @ Expert Belt
Ability: Serene Grace
EVs: 188 Atk / 172 SpA / 148 Spe
Naive Nature
- Iron Head
- Fire Punch
- U-turn
- Energy Ball
Iron Head for a strong STAB with 60% flinch chance, Fire punch as it provides the most useful coverage for Rachi, U-Turn is pretty much a given to scout/avoid death/switch into Flygon as you predict the Quake/Fire move :^))). Energy Ball is the best part of this set, as along with Expert Belt it catches out the likes of Swampert, Crocune and Vaporeon, noticeable bulky waters in UU. The aim here is to lure mons in as you bluff a Scarf set, only to hit them when they least expect it.
However, if utility is more your thing, you can also run a Specially Defensive set incorporating Uturn and Wish, along with Body Slam + Iron Head, running 252HP / 224 SpDef / 32 Spe EVs and a Careful nature or a pivot set, based solely around pivoting with your other mons to force switches into hazards.
Blastoise-Mega is an interesting choice, given the other Megas you have access to. However it is a nice bulky water mon, with the added benefit of Rapid Spin rather than Defog and a nice OP Mega ability.
