This is a set I've had some success with
Offensive Hazard setter
Nihilego @ Focus Sash
Ability: Beast Boost
252 Speed, 252 Special Attack, 4 HP
Timid Nature
Move 1: Sludge Wave
Move 2: HP Steel
Move 3: Stealth Rock
Move 4: Toxic Spikes
This set fares quite well as a hazard setter against both offensive and defense alike. Sludge Wave is primary STAB, while HP Steel prevents Mega Diancie from anti leading you. It might seem unlikely that Nihilego can get up all 3 layers of hazards before dying, but Focus Sash is there so that you can at least put up 1 layer of hazards in the face of something like a Garchomp, or that you can eliminate Mega Diancie with HP Steel without getting eliminated by their ground type moves.
Against offense, I'll usually lay down Rocks first, whereas vs defense, I'll probably be laying down Toxic Spikes. Because the rest of my team can apply good enough pressure, it's usually okay if Nihilego faints while laying down hazards. However, while its bulk isn't great, it can comfortably take most non-Ground type attacks and is fast enough to lay down multiple hazards somewhat reliably.
http://replay.pokemonshowdown.com/gen7pokebankou-488895527
This is a great example of how this set functions at its best. I'm able to get down all my hazards and really apply pressure on my opponent. Getting down 2 layers of Toxic Spikes allows me to be a little looser with Xurkitree, being able to dare my opponent to send Alolan Maro in to block my Volt Switch in exchange for being badly poisoned and hurt bad by Stealth Rock. Had my opponent not DCed, it also would've lefted his Tapu Bulu crippled and easy to break through. Because my opponent isn't able to send in Alolan Maro without severe consequence, I'm able to Volt Switch with Xurkitree freely and with little prediction, being in a good position to accept the loss of momentum thanks to my Gliscor being healthy.
It also works really, really well with Pheramosa and how much pressure it can apply in general with forcing switches.
The utility that Nihilego brings with its hazards complements an offensive build quite nicely, and to me, that gives it a clear and defined niche in the OU tier.