Nasir has been my favourite runner identity since he was released. While I find it a lot of fun and he allows perhaps more Shaper Bullshit than any other identity, I must say he isn't particularly competitive. I don't expect to ever see a stable tier 1 Nasir deck with decent matchups across the board, simply because his power is that he's fundamentally not reliable. While his ability can indeed generate a lot of income depending on what ice you encounter, this comes at the cost of the corp having greater control of your economy than you do.
That said, the drawback can be built around and Nasir can be played to some success. Obviously, Personal Workshop, recurring credits (Toolbox, Cloak, Net Celebrity, Cyberfeeder, Scrubber) and Ghost Runners are a natural fit for Nasir, as are Cerberus and the Shaper boost-per-run-breakers (Battering Ram, Gordian Blade). Order of Sol can accelerate the Workshop from 1 to 3 per turn. It is a lot to set up, but Nasir's ability means you can do it while running. In fact, the more ice that gets rezzed, the faster you get set up, and you can use cards like Parasite and Crescentus to increase the number of ice the corp needs to rez. Builds like this tend to have decent to good matchups against glacier decks, especially HB and Weyland. Replicating Perfection can be a problem since a build focused around recurring credits can have trouble making more than one run per turn, and psi games are hard when you don't have control of your economy. And of course, NBN fast advance - which is and has long been one of the strongest and most common archetypes - is the worst matchup since they tend to have few and cheap ice and hard-to-trash assets and upgrades. Not exactly a recipe for winning tournaments.
Another way to go is Faust, which makes you less dependent on credits for making runs. You don't have the pancakeengine in faction, though, which makes it harder to power it. The most viable archetype I've found uses Faust combined with Bookmark to enable Apocalypse. Of course, this comes with its own set of problems. The NBN fast advance matchup is still only decent at best, assuming you have Clot, and teching specifically against Faust is already a good idea in the current meta.
All in all, Nasir is great fun to play! He spins the game around in a way no other runner does. Only Hayley rivals him when it comes to mid-run Shaper Bullshit. He'll make sure you know every last detail of the run timing structure. He can happily facecheck ice while broke, can really mess with corp headmath, and the Faust-Apocalypse archetype does very weird things to the flow of the whole game. But a lone Pop-up Window can still keep you from stealing that NAPD Contract or trashing that damn SanSan City Grid.