to realize any given function only using NAND/NOR logic, do the following...
(1). First draw out an implementation of the boolean function using AND gates, OR gates and INVERTERS.
(2). Apply DeMorgan's Law to the circuit by using the equivalences in the first two rows of the Figure i have attached below. To create a NAND only circuit, use the transforms in the left box, and for a NOR only circuit use the transforms in the right-hand box.
(3). Any time that two inverters are in series (an inverted output goes directly in to an inverted input), remove both of them, since they cancel each other out.
(4). Replace any remaining inverters with the equivalent NAND or NOR implementation (the third row of the Figure).
i guess your process will now become simple...