Don't see why not. The only problem you might have is trying to tune while either of your other pedals are on. The reason people put their tuners first is 'cause it means the guitar hits the tuner first and gives the tuner the truest representation of its pitch possible. If it runs through a chorus first, given that chorus is a mild pitch modulation effect, it will effect your tuning, so make sure you switch the chorus off when you tune. Other than that, the Pitchblack is true bypass so it should be all good wherever you want to put it.
