Mammoth Uncensored Word List:
13 - 20 letter words starting with no

nonagintacentillions nondenominationalism nondestructivenesses nonillionsedecillion nonimmunocompromised noninstitutionalized noninterdisciplinary nonsanctimoniousness nonstereoselectively nonstereospecificity nontrigonometrically novemvigintillionths noventrigintillionth