Boil water in a pot and add frozen Nagasaki noodles. Cook over medium-high heat for about 2 minutes while loosening the noodles. Drain and rinse under cold water, then drain thoroughly.

Remove the pit from the ume plum and tear it into small pieces in a bowl. Add the condiments (soy sauce, olive oil, garlic powder, and red shiso furikake) and mix well. Cut mizuna greens into bite-sized pieces and add to the bowl. Thinly slice shiso leaves and add them as well. Tear the salad chicken into bite-sized pieces and add to the mixture. Finally, add the cooled noodles and toss everything together.