Yes! However, they do require a bit of experience and skill to use effectively.
If you were to pick up a pair or set of nunchucks (nunchaku) for the first time, and just swing them around like a maniac, then you could get lucky and take care of business with an attacker.
Afterall, just wailing away at a possible attacker can cause them to run away and leave you alone.
But someone who was determined to get at you will wait out a response from you if you are experienced, and look for an opportunity to make their move and defeat you.
Therefore, you need to obtain some experience in order to effectively use your nunchucks.
Some type of training will be good to obtain, and you can obtain this training and skill from several sources.
First, you can seek the experience of a friend or trusted advisor. Often, if they have the skills and experience, they will want to share that with you so that you are more experienced and know what you need to do when you encounter dangerous situations.
Second, you can watch videos to learn various techniques. Bruce Lee is perhaps the most famous user of nunchucks/nunchaku and he starred in many movies before his untimely death. There are a ton of videos with him showing excellent form and learning from what he did will only help you. In addition, there are thousands of YouTube videos of other people who explore the craft and look to make other people better.
Finally, feel free to join a local dojo or other type of instructional class. You will likely use foam nunchucks in training before graduating to wood or metal nunchaku. Hands-on experience is the best way to learn and you can get a lot of exposure while working with people who have the experience that you are looking to obtain.
Once you get a bit of training under your belt, then you can expect to be quite proficient using nunchucks against an attacker. Be sure to practice often to keep your skills sharp. You never know when you might need them!
Thank you for reading and please let me know if you have any questions or need help!