Question

Out of nitrogen and fluorine which has high ionisation enthalpy

Answer 1

nitrogen has higher ionization enthalpy power because its valency is + 3 valency is nothing but showing how many ions a atom is losing or gaining so nitrogen has high valency so it has high ionization enthalpy power

Answer 2

No!
Fluorine has a higher ionisation enthalpy. Ionisation enthalpy/potential increases accross a period in the periodic table and decreases down a group in the periodic table.
Since Nitrogen is in the 15th and fluorine is in the 17th group, more energy has to be supplied to remove an electron from Fluorine.