To update the state of a nested JSON object in React using hooks, you can use the following steps:

1. Import the useState hook from the react library.

import { useState } from 'react';

2. Declare a state variable and a setter function for the nested JSON object using the useState hook

const [nestedObject, setNestedObject] = useState({
key1: {
subkey1: 'value1',
subkey2: 'value2'
},
key2: {
subkey3: 'value3',
subkey4: 'value4'
}
});

3. To update the state of the nested object, you can use the setter function and pass in a new object with the updated values. For example, to update the value of subkey1 in the key1 object, you can do the following:

setNestedObject({
...nestedObject,
key1: {
...nestedObject.key1,
subkey1: 'new value'
}
});

4. You can also use the setter function to update the state of the entire nested object by simply passing in a new object.

setNestedObject({
key1: {
subkey1: 'new value1',
subkey2: 'new value2'
},
key2: {
subkey3: 'new value3',
subkey4: 'new value4'
}
});

Keep in mind that whenever you update the state using the setter function, React will re-render the component to reflect the changes.