Prevent Chlodwig I. from converting to Christianity. Wasn´t it a close match after all ?
Not really. Him and his predecessor were in really good relations with the Gallo-Roman bishops, that like all bishops in post-imperial Romania, were the main urban agents with counts while the cities were a necessary part of the Late Roman administration kept by Romano-Barbarians kingdoms.
If you add to this the demographical pressure, the romanisation of Barbarians, the geopolitical interests (such as being supported by Gallo-Roman clergy against Homeans), the siege made by Niceans around him (up to his spouse)...
"Close match" doesn't really describe it.
Of course even if it was one, butterflying Christianisation of Franks would have huge repercussion and 350 years afterwards (would it be only Gothic hegemoncy in Gaul being maintained trough Alaric II religious policy), you'd have probably butterflied Peppinid rise, fall of Merovingians and Charlemagne himself.