I am a natural niggler, alas!Si parva licet componere magnis, I too am a natural niggler.
Oxford English Dictionary (OED) defines niggler, n.2 as "A person who niggles (niggle v.2); esp. a person who pays excessive attention to detail; a pedant" and niggle, v.2 (sense 1.a) as "To do something in a painstaking, finicky, fussy, or ineffective manner; to trifle, fiddle; to waste effort or time on petty details."
According to Anatoly Liberman, Unpronounceable Words As An Object of Etymology, niggle is related to that unjustly maligned word niggard:
Niggard, first recorded in Chaucer (who had his ear attuned to popular speech), is akin to niggle “to do anything in a trifling or ineffective way” (from gniggle ~ kniggle?) and is, most likely, a borrowing from Scandinavian. There is a good chance that at one time it sounded like gniggard or kniggard; hn- does not count: it is only a weakened form of them both (for instance, knife has a counterpart in Icelandic, and there it begins with hn-). If I am right, niggard was a name for a penny pincher, a miser who would amass wealth in a “niggling,” painstaking way.Quite different are the meanings of the homonyms niggler, n.1 ("A lascivious person") and niggle, v.1 ("To have sexual intercourse with").