In Jain Dharma, porn is not called a separate “nikachit karma.” It is an unwholesome activity that increases kāma-rāga, vikāra, and attachment, and can cause āsrava and bandha of karma.

If a person repeatedly indulges in it with strong passion, then the bondage can become very firm and deep — in that sense, it may lead to strong, fixed karma. But porn itself is not a named karma category.

In simple terms:

• Porn = bad conduct / cause of karma
• Nikachit karma = firmly bound karma
• Porn can lead to such firm bondage, especially through moha and kaṣāya

From the Jain viewpoint, it is best avoided for protecting brahmacharya, samyaktva, and inner purity.