Short answer: Wearing a dhoti is appropriate for Jain men. Covering the chest and stomach with an uparna/angavastra (upper cloth) is respectful and perfectly acceptable. Always follow the maryada (local temple rules).

A little detail:

• Jain principles for laypeople (śrāvaks) emphasize shauch (cleanliness), lajja (modesty), and aparigraha (simplicity). Simple, clean clothing that is not revealing is ideal.
• Many derasars ask men to remove shirts/vests during pūjā or abhiṣek but to keep an upper cloth draped over the torso. Other temples ask for full covering. Both practices exist; the local maryada decides.
• Prefer plain, light/white cotton for worship. Avoid leather, silk, wool, and fur due to ahiṃsā.
• Digambar and Śvetāmbara community customs differ in details, but the core—modesty, cleanliness, and non‑violence—remains the same.

So, a dhoti with the chest and stomach covered by an upper cloth is good and respectful. If you are entering a specific temple, follow its posted dress code and the guidance of the pujari/trust.

For simple temple‑etiquette guidance, see:

• Basic rules while visiting a Jain temple
• What to do in a derasar