Is there a non-surgical way to make a wide nose slimmer?

In certain circumstances the answer is yes. For example the perception of a wide nose that has a depressed, diminutive, nasal dorsum will appear proportionally slimmer if it is used to build up the bridge.

Injecting temporary  fillers into  the nose only makes the nose wider, taller  and bigger, not smaller and slimmer. There are also significant complications that can occur with injections in the nose such as necrosis of the skin. The nose is composed of the bone and cartilage and must be surgically narrowed in order to make the bridge slimmer.  A closed rhinoplasty approach can accomplish her goals with all the incisions placed on the inside of the nose itself. For many before and after rhinoplasty examples, please see link below

Non surgical procedures such as fillers like Radiesse are very helpful to improve the shape and contour of your nose, but can be temporary, and are only suitable for certain cases. Surgical rhinoplasty is often the best solution for a more permant solution. Without a photograph, it is difficult for me to give you a recommendation for the best procedure for you, but if you are looking for a slimmer nose you will probably need a functional rhinoplasty. A consultation is always necessary to give you definitive recommendations on how to improve the contour of your nose.

There are non-surgical and surgical ways for a nose to appear improved in shape and contour, however fillers will "FILL" an area.  The only true way to slim a nose is with a surgical rhinoplasty where shaving can be performed to the bony nasal structure.  There are possibilities for utilizing temporary fillers to improve the shape and therefore could offer the perception of a better contoured and possibly slimmer nose.  Speak with your provider in detail regarding the appearance and shape you are looking for and they will be able to work with you to obtain the image you desire.