Spell Attack Rolls always use your Spellcasting Stat, so there is no real difference between a "ranged" and "melee" spell attack roll, they use the same stat.
Spell Attack Rolls always use your Spellcasting Stat, so there is no real difference between a "ranged" and "melee" spell attack roll, they use the same stat.
Chill Touch is Save Based. There is no Attack Roll.