In Jain Dharma, intentionally picking your nose is generally not considered a major paap by itself, but it is discouraged if it is done carelessly, repeatedly, or in a way that involves harming living beings or showing lack of cleanliness and restraint.

From a Jain view:

• Ahimsa is the main principle.
• Any action done with carelessness (pramāda) can bind karma.
• If the action causes harm to tiny jīvas or comes from impurity and lack of self-control, it is spiritually unfavorable.

So, small bodily habits are not judged the same as severe sins, but Jain practice encourages:

• cleanliness,
• restraint,
• mindfulness,
• and avoiding unnecessary careless actions.

In short: it is not usually seen as a serious paap, but it is not an ideal Jain practice either.