nested array/object creating html?

If, as I think you are suggesting, there is no restriction as to how bbcodes is formatted so long as it produces the correct markup that you have posted. Then I would re-structure it as follows and produce the markup using plain old javascript as follows.

Javascript

var bbcodes = [
    ["b", "u", "i", "list"],
    ["j", "k", "l", "m"],
    ["close", "stop", "back", "time"]
];


bbcodes.forEach(function (group) {
    var wrap = document.createElement("span");

    wrap.className = "button_wrap";

    group.forEach(function (item) {
        var button = document.createElement("span");

        button.className = "easy_edit_button easy_button_" + item;
        button.textContent = item;

        wrap.appendChild(button);
    });

    document.body.appendChild(wrap);
});

On jsfiddle

Why? If the data is fixed then you don't need all the extra objects and as you had it you were using the same "key" multiple times, when it would need to be unique.

This is using Array.forEach, which can easily be shimmed or you could change to while or for loops.

Update: If you don't like to shim, then here is the above but converted to while loops, this is cross-browser friendly without the need to shim. And uses document.createTextNode instead of Node.textContent.

Javascript

var bbcodes = [
        ["b", "u", "i", "list"],
        ["j", "k", "l", "m"],
        ["close", "stop", "back", "time"]
    ],
    bbcodesLength = bbcodes.length,
    bbcodesIndex = 0,
    groupLength,
    groupIndex,
    group,
    item,
    wrap,
    button,
    text;

while (bbcodesIndex < bbcodesLength) {
    group = bbcodes[bbcodesIndex];
    wrap = document.createElement("span");
    wrap.className = "button_wrap";
    groupLength = group.length;
    groupIndex = 0;
    while (groupIndex < groupLength) {
        item = group[groupIndex];
        text = document.createTextNode(item);
        button = document.createElement("span");
        button.className = "easy_edit_button easy_button_" + item;
        button.appendChild(text);
        wrap.appendChild(button);
        groupIndex += 1;
    }

    document.body.appendChild(wrap);
    bbcodesIndex += 1;
}

On jsfiddle