BN may not have plans to buy nuclear subs. The subs may be diesel-electric. Normally, this type runs on diesel which creates a lot of sound. But, when it is underwater and near the enemy fleets in a warlike situation it is switched to electric which is completely silent. BN certainly does not need aircraft carriers, since it is to protect only the small BoB whose security has been recognized as the security concern of BD only. Naval purchases are not to satisfy for someone's personal ego or fantasy.
By the way, your words seem to be spitting venoms. Does our defence plan makes you or your super-poor India nerveous? Look, we do not have graet ambition. We just want to keep our Bay free of Indian expansionism. A few sub addition will certainly sharpen our teeth.