Revelation 20:1 New English Translation

20 Then^[a] I saw an angel descending from heaven, holding^[b] in his hand the key to the abyss and a huge chain.

Revelation 20:1 tn Grk “And.” Here καί (kai) has been translated as “then” to indicate the implied sequence within the narrative.
Revelation 20:1 tn The two clauses “having/holding the key of the abyss” and “a huge chain in his hand” can be construed in two ways: (1) both are controlled by the participle ἔχοντα (echonta) and both are modified by the phrase “in his hand”—“having in his hand the key to the abyss and a huge chain.” (2) The participle ἔχοντα refers only to the key, and the phrase “in his hand” refers only to the chain—“having the key of the abyss and holding a huge chain in his hand.” Because of the stylistic tendency in Rev to use the verb ἔχω (echō) to mean “hold (something)” and the phrase “in his hand” forming a “bracket” along with the verb ἔχω around both the phrases in question, the first option is preferred.

New English Translation (NET)