Chop the chocolate bar, put it in a steel bowl or aluminium deep pan whatever you have and with double boiler method melt the chocolate. Once melted either you can use silicon brush to make the egg shell in the mould or pour the chocolate in the cavities of the mould and swirl wait for a minute and pour the excess out. Keep it in the fridge to set for 10-15 minutes.

Again with any of the above mentioned methods you can give the second coating, scrap the dropped chocolate off from the top of the mould with a kitchen knife or bench scrapper and keep it in the fridge for about an hour or so, till the chocolate shells comes off easily from the mould (give a small bang to help it to come off). Keep it refrigerated.

With the remaining chocolate put it in a piping bag, make a very small cut, and pipe it in ice cold water in order to give it a nest shape. (Do not pipe when the ice cubes are in the water...I just added few more ice cubes in chilled water.)
Take it out of the water and keep it fridge till you present your Easter egg in it.

For the white chocolate, do as same you did for dark chocolate. In order to make it colorful add few drops of gel colors as per your desire after the white chocolate makes. Follow the same process.

After all the chocolate egg shells are ready, put toffee, gems/ M& M, any candies which fits in it. Warm up a pan, put one side of the shell with the edge down, as soon as it melts a bit immediately stick it on the edge of the other shell and run your finger around the sticking edges. Your Easter egg Pinata chocolate is ready !!! Put the chocolate eggs on the Chocolate nest and present to your family and friends!!! HAPPY EASTER!!!