LEGO sets ship in sturdy cardboard boxes. The LEGO bricks inside the box are sealed in plastic bags (though some larger pieces come loose in the box) and for larger sets the instruction manual and sticker sheet are also sealed in a plastic bag.
The LEGO box itself is not covered in plastic. LEGO uses “seals” to prevent tampering - these are basically just ...
As far as regular sets go (ie. no furniture or big-boxes like that Chima combo), the current UCS Millennium Falcon does appear to be the largest box by total volume.
75192-1 Millennium Falcon - UCS (2nd edition)
54 x 45 x 39 cm = 94770 cm3
54 x 45 cm = 2430 cm2
The original UCS Millennium Falcon box was actually larger in 2 directions however, though the ...
In addition to the other answers which highlight the lack of any external plastic covering and the use of seals or glue to indicate the product's unopened state, the products bought directly from LEGO are shipped in plain brown cardboard boxes along with plastic air cushions to protect them during shipping, like demonstrated in this video for example. Other ...
Maybe straining the definition a little (although not too much, as at-least some of them did come with LEGO pieces), LEGO has in the past sold furniture.
I think all of these items were shipped disassembled, and I can't find much information on exactly how large the box they came in was and can't be sure what I did find is accurate, but I would imagine one ...
Straining the definition a little less than Alexander, some of the First LEGO League challenges came in boxes with the mat folded, making the box unexceptional, but some came in boxes with the mat rolled up.
According to bricklink the 2015 challenge came in a box that was 117 cm long. That is quite a bit more than any of the dimensions of the Millenium ...
I thought that promotional boxed sets were good candidates for the smallest box as well, as I own a 1630-1 Helicopter (which, incidentally, I got as a promotional gift for buying toothpaste at some point in the 90s IIRC), at 7 x 7 x 4.5 cm (220cm3/0.22 litres).
There are sets with similar dimensions as well, such as 5018-1 Gravity Games Promotional Set at 7 ...
The boxes for usual LEGO sets are not packaged in plastic wraping. It looks like you consider plastic to be the packaging, while the box itself is the packaging, since LEGO bricks inside is the actual product and not the box.
Considering environmental issues extra plastic wraping would be wastefull since (I assume) 99% of all sets are being opened.
YouTuber Swedish Brick put up a nice unboxing video of your set here.
The motor/battery box seem to be in the white enclosed box, he pulls them both out off camera.
By his video, you will end up with:
2 Motors 1 Battery holder, and 1 Motor in a sealed bag.
A sealed instructions bag with 1 sheet of stickers, and 2 large ...
As with “biggest”, smallest also has different definitions (weight? Width? Volume?). Here are a few candidates:
5005250 Party Banana Juice Bar - 8 x 4.5 x 11 cm (the Chicken version also qualifies)
600-2 Police Patrol - 9.5 x 5.6 x 3.6 cm
I don’t have a link or box picture, but the Dutch store opening gift Windmill comes in a pretty small box as well.