Coffee whipped cream filling
You should be fine, but you may have difficulties dissolving the instant coffee in cold cream. 

Let me suggest a tiny tweak:
Dissolve the instant coffee in a tablespoon or two of boiling water, let it cool until at least room temperature (or even refrigerator temperature) and add it to your semi-whipped cream. 

If you use a cream with a sufficiently high fat content - 35% or even 40% - the additional water will not cause any problems with whipping the cream properly. The lower the fat content of your cream or cream-and-other-liquid-mix, the harder it is to whip. Try to stay above 30% and chill your cream and the bowl well. Your heavy cream should be absolutely fine.