In the case of Sky, the ASA criticised the way subscription options were presented to customers signing up for streaming service Now TV, which belongs to Sky.
Customers who signed up found that free trials for its Cinema and Boost services were automatically added to their basket and would auto-renew for a fee unless cancelled at the end of the seven-day free trial period.
Although the conditions of the free trial were stated, the ASA said the information was in a smaller font and a less prominent colour.
The text was also underneath the button to proceed, making it likely that people would miss it, the ASA said.
Sky said it believed the presentation of the ad was clear, legible and immediately visible.
It added that the concept of a seven-day free trial was so widely understood that it was not misleading.
Nike said the ad for its shoes had been created and published by The Sole Supplier, an online footwear marketplace, without any input or oversight from the sportswear giant itself.
However, Nike argued a reasonable consumer would assume there would be a limit on availability in some way.
The ASA also banned an ad from the food replacement firm Huel, the third of their ads to be banned in the last two months.
The ASA said the health benefit and cost savings claims made in the ad could not be substantiated.
