how nice it is to meet them ("yin dee tee dai ruu jak gun (ka)" = acceptable for someone as esteemed as a monk?)
It sounds weird to say to a monk. However, he may know how you feel from your gestures and actions.
But I would ask a Thai native if you should be using "dichan". I almost never hear women using that pronoun, but maybe with monks it is the correct form.
Dichan is very formal but safe. If you're familiar with other people, chan or your nickname can be used.
อิอิ
