Can I eat watermelon after eating yellow peach?
Generally speaking, it is safe to eat watermelon after consuming nectarines, but moderation is advised. Detailed analysis is as follows:

Both nectarines and watermelons are nutritious fruits rich in vitamins, minerals, and other essential nutrients. They typically do not cause adverse reactions when consumed together and have no significant negative impact on health. Consuming them can provide abundant nutrients, help replenish energy and fluids, and are especially suitable for consumption during hot summer months.
As nectarines contain considerable dietary fiber, excessive consumption may increase the burden on the gastrointestinal tract, potentially causing digestive discomfort. Overconsumption of watermelon may also lead to abdominal pain, bloating, frequent urination, and other discomforts. Therefore, when consuming nectarines and watermelon, it is important to control portion sizes and avoid overeating.
In daily life, maintaining a diversified diet and balanced intake of various nutrients helps sustain good health. It is advisable to consume more fresh vegetables and fruits to supplement the body's needs for multiple nutrients.