The noise floor you are speaking about is referred to the input, that is no gain of the chain is taken into account. If you want to know if the ADC can affect the noise figure, instead, you have to consider also the gain to compare the level at the ADC input as dBFS (you have to know the voltage reference) with the floor of the ADC itself (roughly could be 1LSB).
If the incoming noise level is higher than that of the ADC, the noise of the ADC can be neglected.
In that case the noise floor will be given by -174+10Log(470e6)+NFlna (consedering adequate Nyqist filtering as said by mtwieg).
If the whole receiver chain is perfectly linear (that means no compression due to the power integrated over the whole 470MHz range), you can filter the acquired signal by means of a digital filter of 1MHz BW to achive a sensitivity close to -174+10Log(1e6)+NFlna+SNRmod
where SNRmod is the minimum signal to noise ratio given by the modulation you are using.