How to list my acting credits, chronologically or by genre
Obviously it depends on where you are listing them! If you are listing them on Casting Call Pro, then there is no option to do anything bur chronologically. However, if you are listing things on Spotlight, there are two options you can choose from - as an entire list, or as 'genre' or medium (Stage, TV, film, Radio etc. I believe that if you are lacking in credits at the moment and still need a few more to bump up the list, then go for simply listing them chronologically. This way, keeping it as one list makes it appear fuller. Otherwise, just having one credit on each tab makes your Spotlight CV look sparse and like you've hardly worked. Once you've got a few credits though (I'd say at least two in each tab as a rough guide), feel free to list by genre, as certain casting directors, directors, or producers will only be interested in certain work you've done as they will be casting for that type or work.
On your actual CV, list them by medium, and then in chronological order - this is the standard across the industry. Also always go with the last work you did at the top of each list - this will be one of the things any person looking to cast you will be looking for, so they don't want to have to scroll down or look at the bottom of the page or turn the page to see what you have done recently. These people are busy and have short attention spans, but again it is an industry standard anyway. Also, you don't need to list the date or year of the production on your CV, although this is required on Casting Call Pro and Spotlight. I don't know why you don't need to provide this on your CV (I'm not entirely sure anyone does), but again, this is standard.