The marked angle can be named as: ∠NLO or ∠OLN
How to name angles?
To avoid any errors we normally are to follow the convention of writing angles as '∠' followed by three letters or points of the angle, with the vertex as the center letter.
However, Angles can also be named with numbers or letters by writing a number or letter or even a symbol like the Greek letter ''.
Now, using the above, we can name the indicated angle as:
∠NLO or ∠OLN