Trying to map json to mysql

Question

These are the two tables I want to end up with:

tableA (I already have data in this table)

id | initials | name

1  | ER       | Eric Robinsn
2  | DD       | David Dobson

tableB (nothing in here yet)

id | tableA_id | nickname

1  | 1         | Rick
2  | 1         | Ricky
3  | 1         | Mr. Bossman
4  | 2         | Dave
5  | 2         | Davey

This is the JSON I have:

[
    { 
        name: "Eric Robinson", 
        initials: "ER", 
        nicknames: ["Rick", "Ricky", "Mr. Bossman"] 
    },
    {
        name: "David Dobson",
        initials: "DD",
        nicknames: ["Dave", "Davey"]
    }
]

Inserting into tableA is very easy, you can do it like this with node-mysql:

vary connection = require("mysql");
var json = JSON.parse(require("./data.json"));   
var sql = "INSERT INTO tableA(initials, name) VALUES ?";
connection.query(sql, json, callback);

But as a complete SQL noob how would I map the data into tableB? After some researching I'm not sure if I can do this with something like the following:

INSERT INTO tableB (tableA_id, nickname)
SELECT id
FROM tableA

Or maybe I need to include a left join? The part that confuses me the most is how to include the tableA_id part of the query into the statement. I've tried

INSERT INTO tableB (tableA_id, nickname)
SELECT id
FROM tableA
WHERE tableB.tableA_id = tableA.id //this is the part I don't get

This is just an abstracted example. Also, I'm using node-mysql so when I'm inserting into tableB the re-mapped JSON looks looks like this:

[
    {
        initials: "ER", nickname: "Rick"
    },
    {
        initials: "ER", nickname: "Ricky"
    },
    {
        initials: "ER", nickname: "Mr. Bossman"
    },
    {
        initials: "DD", nickname: "Dave"
    },
    {
        initials: "DD", nickname: "Davey"
    }
]