That sometimes works, but the LTB is cracking down on it. If the unit is substantially similar to the one the landlord already occupies, and the landlord only intended to move in after a dispute with that tenant, the Board is likely to find that the intent to move is in bad faith and refuse to evict. From the LTB's own guidelines:

For example, a tenant may wish to prove that the same landlord gave a notice of termination for personal use of another unit earlier, obtained possession and then rented it to another tenant. This is not determinative evidence that the landlord lacks good faith, but it may be considered by the Member in weighing the landlord's evidence. Evidence of previous problems between the current tenant and the landlord may also be relevant to the genuineness of the landlord's intention to use the unit as stated in the notice.

It doesn't formally follow that a landlord who moves out of a similar unit and puts it up to rent is acting in bad faith, but it'd be a strong argument.