Herein, we report on a giant thermoelectric figure of merit of a non-degenerate fluorine-doped single-walled carbon nanotube (FSWCNT) using a tractable analytical approach and the phonon lattice Boltzmann model (LBM). We investigate the influence of the doping concentration, and the overlapping integrals on the ZT. The ZT and the temperature range of operation can be tuned using the doping (impurity) concentration and the overlapping integrals, respectively. The lattice thermal conductivity obtained using the phonon LBM was calculated to be 107.2 W/mK which yielded a ZT greater than 20. Interestingly, the ZT obtained is higher than what has been reported in superlattices, (ZT~1.4) and superlattice nanowire, (ZT~ 4) at 300 K, making FSWCNT a potential candidate for thermoelectric applications.