I think that by then, there were too many Turks for Nicaea to expand eastwards. Note a new wave of Turks migrated to Anatolia because of the Mongol invasions.
LSCatilina has said at alternatehistory.com that he considered Nicaea retaking Constantinople was the point of no return for Byzantine Anatolia as Nicaea diverted its attention to Constantinople, When does Turkish Anatolia become irreversible?.