Al-Jawab Billahi At-Taufeeq (the answer with Allah's guidance)
1) If it is not inserted into the nose and is smokeless then the fast will not break.
2) Makrooh (disliked) things while fasting.
To chew gum, rubber, plastic items or other such things (which are chewed, but not swallowed, and nothing reaches the stomach, for otherwise the fast would be broken).
To taste any article of food or drink and spit it out (without anything being swallowed). If a woman has a very ill tempered husband, it is permissible for her to taste the food, provided it does not go down her throat.
To collect one’s saliva in the mouth and then to swallow it, trying to quench thirst.
To delay a bath that has become obligatory intentionally until after fajr time.
To use paste or tooth powder to clean one’s teeth. It is permitted to use a miswak of any permissible fresh branch or root (tooth stick). [If one wishes to use toothpaste, one should brush one’s teeth before the fast begins.]
To complain of hunger and thirst.
To take the water too much up the nostrils when cleaning the nose.
To gargle more than necessary (because if any water goes down the throat, even accidentally, the fast is invalidated).
To quarrel, argue, use filthy or indecent words.
To backbite, tell a lie and swear are sinful acts even when one is not fasting. Therefore they become even worse when fasting. (Nurul Idhah Pg. 147/ Talimul Haq Chapter on Sawm)