The electrical transport properties of the polycrystalline Nd1-xNaxMnO3 (0.05 ≤ x ≤ 0.25) were investigated. All the samples are found to exhibit insulating behavior down to the lowest measured temperature. However, on application of 4 T magnetic field, metal-insulator transitions along with a low temperature resistivity upturn are observed for the samples with x ≥ 0.15. Thermopower values of samples with x = 0.05, 0.10, and 0.20 are negative in the entire temperature range of investigation, while they changes from negative to positive with decreasing temperature in the case of samples with x = 0.15 and 0.25. The resistivity and thermopower data in the high temperature region are explained within the framework of variable range and small polaron hopping models, while the resistivity minima are explained using the combined effect of electron-electron and electron-phonon scattering is considered.